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We reported the clinical and pathologic features of two different types of renal mucinous tubular and spindle cell carcinoma (MTSCC). The first patient was incidentally discovered by health examination, with lower nuclear grade, no part and distant metastasis. The second patient presented with persistence hyperpyrexia, part and distant metastasis, and high nuclear grade. Surgery were both performed successfully. The first patient had no recurrences and no distant metastases. The second patient died of multiple organ failure 3 months postoperatively. Although MTSCC is usually a low potential malignancy carcinoma, high malignancy may occur and lead to a fatal course. So it needs a proper management and prognostication.

Mucinous tubular and spindle cell carcinoma (MTSCC) is a rare, distinctive renal neoplasm characterized by an admixture of cuboidal cells in tubules and sheets of spindle cells, typically with low-grade nuclei and a myxoid or mucinous background. It is characteristically of low malignant potential, and only rare metastatic cases have been reported. We describe a case in which the patient presented with extensive regional and distant metastases, but both primary and metastatic tumor showed the typical histomorphology of bland cuboidal or spindle cells lacking pleomorphism, mitoses, and necrosis. Almost all previous cases of metastatic MTSCCs have shown nuclear atypia or sarcomatoid morphology of the primary tumor; and metastatic renal MTSCC in which the primary neoplasm does not display atypical features is exceptional, serving to highlight that these rare tumors can behave aggressively even with "indolent" histological appearances.

Background: Mucinous tubular and spindle cell carcinoma (MTSC) is a rare and newly described type of renal cell carcinoma (RCC) with relatively indolent behavior. Although there are small series of this clinical entity in the literature, its histogenetic origin or line of differentiation remains unclear. Patients and Methods: A 67-year-old woman was hospitalized for flank pain; imaging studies revealed a 6.5-cm mass in the right kidney. She was referred for fine needle aspiration of the lesion, which showed an epithelial tumor with round to oval nuclei associated with strands of metachromatic stromal tissue. Cytopathologic diagnosis was consistent with RCC. Results: Subsequent right heminephrectomy was performed and the surgical pathology specimen showed an MTSC of the kidney. The patient has done well postoperatively, with 24 months of benign follow-up. Conclusion: A precise differential diagnosis between MTSC and other renal carcinomas (e.g. papillary RCC with sarcomatoid transformation) is important for predicting patient prognosis. Even though MTSC is a rare cause of renal masses, it should be included in the differential diagnosis, especially because its imaging might be misleading, mimicking other benign renal diseases. Heminephrectomy is the preferred treatment in these subjects.

Mucinous tubular and spindle cell carcinoma (MTSCC) is a low-grade renal epithelial neoplasm that has recently been recognized as a specific entity in the 2004 World Health Organization classification of renal cell carcinoma. A 69-year-old woman was referred to our hospital because of incidental left renal tumor. Abdominal computed tomography showed a hypovascular tumor in the left kidney. Left radical nephrectomy was performed. Hematoxylin and eosin staining revealed cuboidal and oval or spindle-shaped cells in tubular and papillary patterns embedded in the myxoid stroma. Immunohistochemically, the tumor cells were positive for alpha-methylacyl-CoA racemase. On the basis of these findings, we diagnosed the patient as having MTSCC.

Background: Mucinous tubular and spindle carcinoma (MTSCC) of kidney is a rare, low-grade polymorphic tumor. Recent studies have described a wide morphology spectrum of this tumor. Aim: To report the clinico-pathologic features of six cases of MTSCC of kidney. Materials and Methods: Six cases of MTSCC of kidney were studied and literature was reviewed. Immunohistochemistry was done by Envision method. Results: The age of the patients ranged from 44 to 84 years (mean 58.5 years). Four patients were males and two were females. The tumor was located in the left kidney in four cases and in the right kidney in two cases. The tumor size ranged from 4.5 to 15 cm (mean 6.4 cm). All tumors exhibited an admixture of tubules, spindle cells, and mucinous stroma in variable proportions. Tubules were predominant in five cases and spindle cells in one case. Psammomatous calcifications, papillations, and necrosis were seen in two cases. Collections of foamy histiocytes were noted in four cases. Cytoplasmic vacuoles and osseous metaplasia were seen in one case each. All cases were Fuhrman's nuclear grade II. Five cases were of stage pT1, and one was pT3. All cases stained positive for alcian blue at pH 2.5. Immunohistochemical stain CK7 was positive in all cases and CD10 was positive in 1/1 case. All patients were alive and well at follow-up of 12-59 months (mean 33.5 months). No metastases were detected. Conclusions: We report six cases of MTSCC of kidney, a rare distinct variant of RCC, with a favorable prognosis. A male predominance was seen in our cases. MTSCC shares histologic and immunohistochemical overlap with papillary renal cell carcinoma (PRCC) and cytogenetic analysis should be performed in difficult cases to avoid a misdiagnosis.

Introduction: Mucinous tubular and spindle cell carcinomas (MTSCC's) are recently described rare type of renal cell carcinoma (RCC). They may have morphological similarities to papillary RCC (papRCC) and in our case to carcinoma collecting ducts of Bellini. Case report: We report a rare case of renal tumor, mucinous tubular and spindle cell carcinoma in a 56-year-old woman. The tumor, located in the left kidney, was well circumscribed. MTSCC's are characterized by small, elongated tubules lined by cuboidal cells and/or cords of spindled cells separated by pale mucinous stroma. Discussion: MTSCC is a rare type of renal cell carcinoma. Pathologists should be aware of the histological spectrum of MTSCCs to ensure an accurate diagnosis. Careful attention to the presence of a spindle cell population may be helpful in the differential diagnosis in tumors with predominant compact tubular growth.

We present a case of ulcerative colitis (UC) in a patient during the first severe relapse with colonic dilatation and coexisting of giant renal tumor. Kidney tumor was constricting on colon and imitating toxic megacolon (TM). The patient with severe acute colitis (SAC) was admitted to the Department of Gastroenterology and Hepatology with inflammatory bowel disease (IBD) diagnosed in the previous month, based on clinical symptoms, endoscopy, and histopathology results. Computed tomography (CT) revealed a giant left kidney tumor without evidence of infiltration, a dilatation of the transverse colon up to 6 cm, and narrow light of the descending colon. There were no signs of intestinal obstruction or perforation. The control X-rays revealed maintaining megacolon, with dilatation of splenic flexure projection up to 6.5 to 7.5 cm. The patient was treated conservatively with no apparent improvement and finally operated on. Intraoperatively, a large tumor of the kidney (12 cm) constricting intestine was revealed. Left-sided nephrectomy and partial resection of the colon with the emergence of a colostomy was performed. The histopathology exam revealed renal mucinous tubular and spindle cell carcinoma (RMTSCC), a very rare malignant kidney tumor of low malignant potential and relative good prognosis. It was identified in the past 20 years. To date, approximately 100 such cases of cancer have been described. How to cite this article Kukulska M, Smola I, Halon A, Paradowski L, Poniewierka E, Kempinski R, Annabhani A. A Case of Severe Ulcerative Colitis with Colonic Dilatation caused by Renal Mucinous Tubular and Spindle Cell Carcinoma. Euroasian J Hepato-Gastroenterol 2016;6(2):190-193.

We report a case of mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney. A 68-yearold female consulted a primary hospital with a chief complaint of back pain. Computed tomography revealed the tumor of the left kidney, so she was referred to our department. The tumor, 45×42 mm in length, was slightly enhanced, and that had well-defined margins. We performed radical nephrectomy. Pathological findings suggested MTSCC. MTSCC is a rare type of renal cell carcinoma composed of a combination of low-grade tubular cuboidal cells and spindle cells in a mucinous stroma. The immunohistochemistry is effective in its diagnosis.

Non clear cell renal cell carcinomas represent almost 20% of all renal neoplasms. Their classification is continuously being adjusted according to new cytogenetic and molecular data. Since molecular techniques are expensive, diagnosis still relies on morphological and immuno-histochemical criteria detailed hereby. Papillary renal cell carcinomas are the most important group and its classification is more and more complex. It encompasses low-grade papillary carcinomas (type 1 papillary renal cell carcinoma, oncocytic papillary renal cell carcinoma) and high-grade papillary carcinomas (type 2 papillary renal cell carcinoma, juvenile papillary carcinoma corresponding to renal carcinoma associated with Xp11.2 translocations and unclassified carcinomas). Mucinous tubular and spindle cell carcinoma and tubulocystic carcinoma are new entities, actually considered by some authors as low-grade papillary carcinomas. The so-called carcinoma of collecting ducts of Bellini and renal medullary carcinoma should be considered as intrarenal urothelial carcinoma or as high-grade papillary or unclassified carcinoma. Sarcomatoid carcinoma derives from morphological progression of any type of renal cell carcinoma. The group of oncocytomas/chromophobe renal cell carcinomas can be considered as a spectrum from benign (oncocytoma) to malignant neoplasm (chromophobe renal cell carcinoma). They are sometimes encountered in oncocytomatosis or familial Birt-Hogg-Dubbe syndrome in which tumoral cells may have hybrid features. Angiomyolipoma is usually a benign mesenchymatous neoplasm, that can be sporadic or familial (tuberous sclerosis). In the latter situation, some cases of epithelioid angiomyolipoma (potentially malignant) have been described. Renal epithelial and stromal tumors (REST) is a new concept gathering two benign mixed mesenchymal and epithelial tumors: cystic nephroma and mixed epithelial and stromal tumors (MEST).

The solid variant of papillary renal cell carcinoma (PRCC) is distinguishable genetically from mucinous tubular and spindle cell carcinoma (MTSC) of the kidney by the presence of trisomy for chromosomes 7 and 17; however, at the morphologic and immunohistochemical levels, these neoplasms overlap significantly. The key morphologic feature distinguishing these two is thought to be the low grade of the spindle cell areas of MTSC; spindle cell areas in PRCC generally signify sarcomatoid change and are high grade. We report 5 cases of PRCC with low-grade spindle cell foci, closely mimicking MTSC. All patients were male, and ranged in age from 17 to 68 years. All tumors were predominantly solid, featuring compact areas of low-grade spindle cells lining thin, angulated tubules. Mucinous stroma was not appreciated in any case. All cases were diffusely immunoreactive for cytokeratin 7, and focally CD10 positive. All 5 cases showed trisomy of chromosome 7, and 3 of 5 showed trisomy of chromosome 17 by fluorescence in situ hybridization, supporting classification as PRCC. These cases further reported morphologic overlap between MTSC and PRCC. Before a diagnosis of metastatic MTSC or MTSC with unusual morphology is rendered, the possibility of PRCC with low-grade spindle cell foci should be considered. Fluorescence in situ hybridization analysis effectively separates these morphologically very similar yet genetically distinctive entities.

Kidney-specific cadherin (Ksp-cad) is a membrane-associated cell adhesion glycoprotein expressed by the distal nephron tubular cells in its later developmental stages. Chromophobe renal cell carcinoma and renal oncocytoma are reported to be variably positive for Ksp-cad with some studies suggesting a discriminatory role for Ksp-cad. Immunoreactivity in other tumors with granular eosinophilic cytoplasm including clear cell and papillary renal cell carcinomas needs to be clearly elucidated and its expression in emerging novel and other unusual renal epithelial neoplasm subtypes including tumors with uncertain histogenesis is not yet known. In this study, we performed a detailed immunohistochemical analysis for Ksp-cad in a broad range of 136 renal epithelial neoplasms. Reactivity with Ksp-cad was observed in the following tumors: chromophobe renal cell carcinoma [23/25 (92%), diffuse (50% of tumor cells)] positivity and membranous characteristically accentuating the "plant cell-like" histomorphology of the typical (clear) type, renal oncocytoma [15/20 (75%), usually diffuse staining with predominantly membranous accentuation], papillary renal cell carcinoma [5/17 (29%) all focal to moderate, eosinophilic type or type 2-3/7 (43%), basophilic type or type 1-2/10 (20%)], Xp11 translocation carcinoma [1/4 (25%), diffuse positivity] and clear cell renal cell carcinoma [6/36 (17%) all focal, clear cell renal cell carcinoma with prominent eosinophilic cells 1/7 (14%)]. Immunoreactivity was higher when evaluating whole histologic sections than with tissue microarrays for both chromophobe renal cell carcinoma (100% vs. 60%) and renal oncocytoma (100% vs. 55%). No immunoreactivity was observed in mucinous tubular and spindle cell carcinomas (0/23), high-grade collecting duct carcinomas (of Bellini) (0/3), renal medullary carcinomas (0/2), and urothelial carcinomas (0/6). Our study documents the immunoreactivity of Ksp-cad in the range of contemporarily classified renal epithelial neoplasms. The findings argue against the use of Ksp-cad in differentiating chromophobe renal cell carcinoma and renal oncocytomas and further support their relationship to the distal nephron. Ksp-cad may be helpful in distinguishing these two tumor types from clear cell renal cell carcinoma with prominent eosinophilic cells particularly in cases with limited tissue samples (ie, needle core biopsy). In the similar diagnostic setting, caution must be exercised, however, in differentiating chromophobe renal cell carcinoma and renal oncocytoma from the eosinophilic variant of papillary renal cell carcinoma as moderate expression of Ksp-cad may be observed in papillary renal cell carcinoma. The histogenesis of mucinous tubular and spindle cell carcinoma remains debatable as this tumor does not express Ksp-cad, which is highly expressed normally in the thick ascending loop of Henle and the distal convoluted tubules. In conclusion, Ksp-cad is a useful tumor type associated marker for distinguishing chromophobe renal cell carcinoma and renal oncocytoma from the wide range of nonintercalated cell-related adult renal epithelial neoplasms; addition of this marker to a panel comprised of other histologic subtype-associated markers may greatly facilitate histologic subclassification of adult renal epithelial neoplasms.

Mucinous tubular and spindle cell carcinoma is a rare and newly described type of renal cell carcinoma (RCC) with a relatively indolent behavior. However, its histogenetic origin or line of differentiation remains unclear. Twelve cases of mucinous tubular and spindle cell carcinoma were identified and retrieved from the files of 3 institutions. Detailed morphological features, as well as their immunohistochemical profile established with markers of proximal renal tubules (RCC marker antigen, CD15, and α -methylacyl-CoA racemase) and of distal renal tubules (kidney-specific cadherin and cytokeratin 7), were studied. The age range of the patients was 35 to 73 years with a median of 56 years. The male to female ratio was 1:3. All of the patients were alive with follow-up between 4 and 38 months. All the tumors were confined to the kidney with a mean tumor size of 6.9 cm (range, 1.8-17 cm). The tumors were composed of variable proportions of tubular and spindle cell areas with focal to prominent mucinous or myxoid stroma. Foamy macrophages were seen in 10 cases and were prominent in 4 cases. A focal compressed tubulopapillary growth pattern was seen in 10 cases. The tumor cells were uniformly cuboidal with ovoid to round nuclei and inconspicuous nucleoli (Furhman nuclear grade 3 in 6 cases). Focal necrosis was seen in 3 cases. Immunostains showed that tumors were positive for RCC marker antigen (11/12), α -methylacyl-CoA racemase (11/12), CD15 (8/12), CD10 (2/12), kidney-specific cadherin (1/12), and cytokeratin 7 (11/12). Its morphological features as well as a strong preferential expression of proximal tubule markers suggest that this tumor is a type of RCC with proximal tubular differentiation, which appears closely related to or represents a morphological variant of papillary RCC.

A 54-year-old woman was hospitalized for flank pain and acute renal failure when imaging studies revealed a 5.2 cm mass in the left kidney. She was referred for fine needle aspiration of the lesion, which showed an epithelial tumor with round to oval nuclei associated with strands of metachromatic stromal tissue. Cytopathologic diagnosis was consistent with renal cell carcinoma. Subsequent nephrectomy was performed and the surgical pathology specimen showed a mucinous tubular and spindle cell carcinoma of the kidney. The patient has done well post-operatively with 10 months of benign follow-up.

Tumours of the distal nephron are uncommon but can create diagnostic difficulties. They may be divided into three groups-tumours of intercalated cell phenotype, those of principal cell phenotype and others with an unconfirmed distal nephron origin. Oncocytomas, chromophobe carcinoma and hybrid oncocytoma chromophobe carcinoma, all show features of intercalated cells and the distinction amongst these is one of the most common areas of diagnostic dilemma. Collecting duct carcinoma and renal medullary carcinoma are the most aggressive forms of renal cancer but recent evidence suggests they may respond to targeted therapy so their recognition becomes crucial to the management of these patients. There remains debate over the precise phenotype of both tubulocystic carcinoma and mucinous tubular and spindle cell carcinoma.

Mucinous tubular and spindle cell carcinomas (MTSCs) are polymorphic neoplasms characterized by small, elongated tubules lined by cuboidal cells and/or cords of spindled cells separated by pale mucinous stroma. Nonclassic morphologic variants and features of MTSC have not been well studied. We identified 17 previously unreported MTSCs from Surgical Pathology and consultative files of the authors and their respective institutions and studied their morphologic features. A total of 10/17 cases were considered "classic," as described above, with 5/10 showing at least focal (20% to 50%) tubular predominance without apparent mucinous matrix. Alcian blue staining revealed abundant (50%) mucin in all classic cases. Seven of 17 MTSCs were classified as "mucin-poor," with little to no extracellular mucin appreciable by hematoxylin and eosin. Four of these cases showed equal tubular and spindled morphology, 2 cases showed spindle cell predominance (70%; 95%), and 1 case showed tubular predominance (90%). In 5/7 mucin-poor cases, staining for Alcian blue revealed scant (10%) mucin in cellular areas with the other 2 cases having 30% mucin. Unusual histologic features identified in the 17 cases were: foamy macrophages (n=8), papillations/well formed papillae (n=6/n=1), focal clear cells in tubules (n=3), necrosis (n=3), oncocytic tubules (n=2; 40%, 5%), numerous small vacuoles (n=2), heterotopic bone (n=1), psammomatous calcification (n=1), and nodular growth with lymphocytic cuffing (n=1). An exceptional case contained a well-circumscribed, HMB45-positive angiomyolipoma within the MTSC. MTSCs may be "mucin-poor" and show a marked predominance of either of its principal morphologic components, which coupled with the presence of other unusual features such as clear cells, papillations, foamy macrophages, and necrosis, may mimic other forms of renal cell carcinoma. Pathologists must be aware of the spectrum of histologic findings within MTSCs to ensure their accurate diagnosis.

We describe the clinical features, outcome, pathology, cytogenetics, and molecular aspects of 13 pediatric papillary renal cell carcinomas during a 19year period. Seven cases (54%) had translocations involving Xp11.2 (TFE3). They were identified by cytogenetic, molecular, and/or immunohistochemical analyses. All Xp11.2+ translocations were TFE3+ by immunostaining. Cytogenetic and/or polymerase chain reaction analyses identified 3 cases with t(X17) and 1 case with t(1;17), and all had additional translocations. Histologic features in common in TFE3+ tumors also were present in some TFE3– tumors. One TFE3– tumor had complex cytogenetic abnormalities, 55XY,+2, del(3)(p14),+7,+8,+12,+13,+16,+17,+20[11], and 2 cases had normal karyotypes. None had t(6;11)/TFEB+ immunostaining. Five cases had focal, weak MITF tumor immunostaining. The key clinical findings were as follows: (1) The presence of an Xp11.2 (TFE3) translocation frequently is associated with advanced stage at initial examination. (2) All patients who underwent complete, partial nephrectomy with clear margins (adequate only for stage 1) and resection of metastases were alive and relapse-free at last follow-up. (3) The mean ± SD eventfree survival and overall survival rates at 5 years were both 92% ± 7.4%. (4) One patient with a TFE3+ and MITF+ tumor and 66-87,XXY,der(1)t(1;8)del(4)(q?) der(11)t(11;15)der17t(X;17) abnormalities died 9 months after diagnosis. Renal cell carcinoma (RCC) is a rare childhood tumor constituting fewer than 0.3% of all tumors and 2.6% of renal neoplasms in children and adolescents younger than 15 years, 1 and, given its rarity, it has been difficult to determine whether pediatric RCC differs from its adult counterpart. However, reports suggest that the clinical and pathologic features of pediatric RCC are different from those seen in older adolescents and young adults. 2 In children, most cases consist of papillary histologic features, 3 whereas among the 4 types of RCC (clear cell, papillary, chromophobe, and collecting duct), the clear cell type predominates in adults (75%); in younger adults (1845 years), Cao et al 4 found that 53% were clear cell, 12% were papillary, 8% were chromophobe, 2% were oncocytoma, and 26% were in a miscellaneous group (that comprised Xp11.2 translocation carcinoma, renal medullary carcinoma, primitive neuroectodermal tumor, cystic nephroma, metanephric biphasic tumor, and mucinous tubular and spindle cell carcinoma). Cytogenetic and molecular studies have suggested that abnormalities in the Xp11.2 region involving the TFE3 gene might account for a significant proportion of pediatric RCC, with these tumors representing a subset of papillary RCC. Therefore, RCC associated with Xp11.2 translocations/TFE3 gene fusion is listed as a separate entity in the World Health Organization (WHO) classification of tumors of the urinary system. 5 Moreover, multiple chromosomal translocation partners can be fused to TFE3 at Xp11.2 in this subset of RCCs. The 2 most common forms are the t(X;17)(p11.2;q25) translocation that fuses the transcription factor gene TFE3 with the ASPL gene on 17q25, 6-15 and the t(X;1)(p11.2;q21)

Background The recently introduced 2004 World Health Organisation (WHO) classification of the adult renal epithelial neoplasms is meant to replace the previous 1998 WHO classification. Methods and results The 2004 WHO classification is based on pathology and genetic abnormalities. The description of categories has been expanded to improve their recognition and new diagnostic categories are included. Emphasis has been placed on defining familial renal cancer, carcinoma associated with Xp11 translocations, carcinoma associated with neuroblastoma, multilocular cystic renal cell carcinoma, tubular, mucinous and spindle cells carcinoma; and mixed epithelial and stromal tumour. The potentially aggressive epithelioid angiomyolipoma is recognised. Conclusions Recognising these categories may have important implications in patients' clinical management.

Mucinous tubular and spindle cell carcinoma of the kidney is an uncommon, distinctive neoplasm characterized by the proliferation of cuboidal and spindle cells arranged in tubular or sheet-like arrays, typically with a mucinous or myxoid background. The most important differential diagnostic consideration of mucinous tubular and spindle cell carcinoma is papillary renal cell carcinoma, type 1, with sarcomatoid transformation. The aim of our study is to investigate the pattern of possible gains or losses of chromosomes 7, 17 and Y in 10 mucinous tubular and spindle cell carcinomas with interphase fluorescence in situ hybridization (FISH). Four-micron sections were obtained from paraffin blocks representative of the tumors and including adjacent non-neoplastic renal parenchyma from 10 patients. The patients' ages ranged from 20 to 80 years (mean: 62 years); eight were female, while two were male. FISH analysis was performed with centromeric probes for chromosomes 7, 17 and Y. One hundred fifty to 200 nuclei from each case were scored for hybridization signals and non-neoplastic parenchyma served as control tissue. We found that renal mucinous tubular and spindle carcinoma lacks the gains of chromosomes 7 and 17 and losses of chromosome Y that are typical of papillary renal cell carcinoma. FISH analysis with centromeric probes for these chromosomes is potentially helpful in differentiating mucinous tubular and spindle cell carcinomas from papillary renal cell carcinomas.

The clinical and histological findings of four cases of renal mucinous tubular and spindle cell carcinoma (MTSCC) are reported. Two cases were incidentally discovered during the radiological study of other diseases, and the other two presented with haematuria. Radical nephrectomy was done in the four cases. All the tumours showed the typical histology and immunohistochemistry described in this newly recognised entity. The patients remain free of disease after 3, 8, 10 and 48 months of follow up. The literature related to the diagnosis of this tumour is thor oughly reviewed. Also, the proposed histopathogenetic theories for this tumour are also briefly commented on. The new 2004 WHO classification system of renal tumours is based on morphologic criteria and supported by common genetic findings. 12 Among other rare entities, it includes a variant of renal carcinoma termed mucinous tubular and spindle cell carcinoma (MTSCC). This tumour type had been previously diagnosed as papillary renal carcinoma, metanephric adenoma, unclassified or sarcomatoid carcinoma, 5,8,11,13 and seems to portend a favourable clinical outcome. We report the clinicopathological findings of four additional cases of this rare newly recognised tumour, highlighting its varied histological patterns and differential diagnosis. The cases were col lected retrospectively from consultation of our archive in the last 3 years.

We encountered 2 cases of mucinous tubular and spindle cell carcinoma (MTSCC) during a short time. In a 61-year-old man who had macroscopic hematuria for 1 month, the 14.5 x 14.0 x 12.0-cm resected tumor involved the right middle aspect of the renal parenchyma and compressed the renal pelvis. In an asymptomatic 47-year-old man, a renal tumor was found during an annual physical examination. The 3.5 x 3.0 x 2.0-cm tumor was located at the upper pole of the right kidney. The histologic findings in both cases were similar Tumors consisted of tightly packed, small, elongated tubules separated by pale mucinous stroma. The tumor cells were cuboidal to spindled with eosinophilic cytoplasm and low nuclear grade. Mitoses were few or nonexistent and without abnormal figures. Both tumors were immunoreactive for cytokeratin (CK) cocktail (AE1/AE3), high-molecular-weight CK (34betaE12), low-molecular-weight CK (35betaH11), CK7, epithelial membrane antigen, E-cadherin, and vimentin. The tumor cells also were reactive for neuron-specific enolase, chromogranin, and synaptophysin. The ultrastructure of the tumor cells contained abundant mitochondria, junctional complex, and dense-core neurosecretory granules. We present 2 additional cases of MTSCC showing typical morphologic features with neuroendocrine differentiation.

Mucinous tubular and spindle cell carcinoma, a rare, recently described distinctive subtype of renal cell carcinoma, may have some morphologic similarities to the more common papillary renal cell carcinoma, particularly the basophilic (type 1) tumors with prominent solid growth pattern. Tumor circumscription, compact tubular architecture, focal papillations, mucin production and foam cells (features seen in both papillary renal cell carcinoma and mucinous tubular and spindle cell carcinoma), as well as spindle cell morphology, have resulted in some cases sent to us in consultation with a question of possible sarcomatoid papillary renal cell carcinoma. In this study, tissue microarrays with triplicate samples each from 27 mucinous tubular and spindle cell carcinomas and 20 papillary renal cell carcinomas were created to simulate experience in renal biopsy specimens. From immunohistochemistry (IHC) data, published in the contemporary literature, a panel consisting of alpha-methylacyl-CoA racemase (AMACR), cytokeratin 7 (CK7), epithelial membrane antigen (EMA), renal cell carcinoma marker (RCC Ma), CD10, high molecular weight cytokeratin (HMWK), and c-kit was designed to test its utility in differential diagnosis. The immunoreactivity in mucinous tubular and spindle cell carcinoma was AMACR 93%, CK7 81%, EMA 95%, RCC Ma 7%, CD10 15%, HMWK 15%, and c-kit 5% and in papillary renal cell carcinoma was AMACR 95%, CK7 65%, EMA 88%, RCC Ma 25%, CD10 80%, HWMK 15%, and c-kit 18%. This largest study to date on IHC of mucinous tubular and spindle cell carcinoma dispels the specificity of AMACR for papillary renal cell carcinoma among the RCC subtypes. The histogenesis of mucinous tubular and spindle cell carcinoma from the distal nephron continues to be debatable, as our study showed the expression of the proximal convoluted tubule-related marker AMACR among these tumors. Thus, in tumors with predominant compact tubular growth and focal papillary architectures, careful attention to the presence of a low-grade spindle cell population may be helpful in the distinction of mucinous tubular and spindle cell carcinoma, as the key immunohistochemical stains for papillary renal cell carcinoma are also expressed in this subtype of renal cell carcinoma.

Mucinous tubular and spindle cell carcinomas are low-grade renal epithelial neoplasms, which were first recognized as a specific entity in the World Health Organization 2004 classification. Forty-five documented cases have been reported. We present 15 additional cases that were incidentally discovered in ten women and five men, with a mean age of 53 years. The tumor is characteristically made up of large eosinophilic regular spindle cells separated by a myxoid stroma with intercellular alcian-blue-positive clear droplets. In peripheral areas, elongated tubules and papillae covered by cubic cells are found. Until this entity had been defined, pathologists used to classify these tumors as variants of solid papillary carcinomas with compressed and elongated papillae, metanephric adenomas, and sarcomatoid carcinomas. In the literature, cytogenetic data indicate various chromosomal losses and gains, but no loss of 3p or trisomy 7 and/or trisomy 17. In two cases, we demonstrate chromosomal loss involving chromosomes 1, 4, 6, 11, 8, 13, 14, 15, 18, and 22. In our 15 cases, immunohistochemistry favored a distal tubule origin (EMA(+), AE1/AE3(+), CK7(+), CK19(+), E-cadherin(+), AMACR(+), and CD10(-)). Prognosis was favorable in our cases, while in the literature, two metastatic cases were reported. Further investigations are required to determine the frequency and true prognosis of these tumors, which are easily identifiable morphologically.

Adult renal epithelial neoplasms (RENs) comprise several distinct clinicopathologic entities with potential prognostic and therapeutic differences. Individual cases can show overlapping morphologic features, necessitating the use of ancillary methods. The purpose of this study was to determine the diagnostic utility of cytokeratin (CK) subtype expression pattern in a wide range of adult RENs. RENs (including clear cell [conventional] renal cell carcinoma (RCC), papillary RCC, chromophobe RCC, renal oncocytoma, collecting duct carcinoma (CDC), renal medullary carcinoma (RMC), urothelial carcinoma, metanephric adenoma (MA), tubulocystic carcinoma (TC) (also known as low-grade collecting duct carcinoma), and mucinous tubular and spindle cell carcinoma) were immunostained for CK subtypes (CK5/CK6, 7, 8, 13, 14, 17, 18, 19, 20), high molecular weight CKs 1, 5, 10, 14 (HMWCK), and vimentin (Vim). The expression pattern of normal kidney was also examined and correlated with RENs. Although there is some overlap, subtypes of RENs show distinctive CK expression profiles that may be useful in several differential diagnostic settings. Clear cell RCCs typically showed a restricted expression pattern of CK8, CK18 and Vim. Papillary RCCs typically expressed CK7, CK8, CK18, CK19, and Vim and could be distinguished from MA (CK7-). Chromophobe RCCs were typically CK7+, CK8+, CK18+, and Vim-, and could be distinguished from oncocytomas (typically CK7-). In oncocytomas, nonspecific staining of unblocked endogenous biotin is a potentially significant diagnostic pitfall. CDC, RMC, and TC demonstrated similar CK expression profiles (with the exception of HMWCK expression limited to CDC), supporting a close relationship between these entities. A panel of CK5/CK6, CK17, and Vim may be helpful in distinguishing CDC (typically CK5/CK6-, CK17-, Vim+) and urothelial carcinoma (typically CK5/CK6+, CK17+, Vim-). In conclusion, CK expression patterns may be helpful in several differential diagnostic situations when dealing with adult RENs.

Mucinous tubular and spindle cell carcinoma (MTSCC) is a rare indolent subtype of renal cell carcinoma, which has variable magnetic resonance (MR) imaging features due to histomorphologic diversity. Diffusion-weighted MR imaging has shown its ability to differentiate benign and malignant renal neoplasms in some recent studies and can be a useful adjunct to routine MR sequences in ambiguous cases. We present a histopathology proven case of MTSCC highlighting the role of diffusion-weighted imaging in guiding the surgical management.

(2003). Mucinous tubular and spindle cell carcinoma and post‐neuroblastoma carcinoma: newly recognised entities in the renal cell carcinoma family. Pathology: Vol. 35, No. 6, pp. 499-504.

Mucinous tubular and spindle cell carcinoma (MTSC) was first recognized as a specific entity in the World Health Organization 2004 classification. The “classic” tumor presentation includes an extracellular blue-gray mucinous/myxoid matrix accompanying the typical tubular and spindle cell epithelial components. Tubules are lined by cuboidal to columnar cells with bland nuclei, central small to medium sized nucleoli, and few to no mitoses. By expanding the histologic spectrum, a number of studies highlighted the distinction between MTSC and solid variant of papillary renal cell carcinoma (sPRCC), although controversy still exists. Here, we evaluated two cases of MTSC and compared two cases of sPRCC by light microscopy, special staining, immunohistochemical staining and fluorescence in situ hybridization (FISH). We found that morphologic and immunophenotyping features showed more overlap between MTSC and sPRCC. In addition, gains of chromosomes 7 and 17 and loss of Y, which are characteristic of PRCC, were observed in two cases of sPRCC and one case of MTSC, suggesting that MTSC is similar to sPRCC or may be a subtype of PRCC. Virtual Slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_194

Xp11.2-translocation renal carcinoma (TRCC) is suspected when a renal carcinoma occurs in young patients, patients with a prior history of exposure to chemotherapy and when the neoplasm has morphological features suggestive of that entity. We retrieved 20 renal tumours (from 17,500 archival cases) of which morphology arose suspicion for TRCC. In nine cases, TFE3 translocation was confirmed by fluorescence in situ hybridisation analysis. In 9 of the remaining 11 TRCC-like cases (7 male, 4 female, aged 22-84 years), material was available for further study. The morphological spectrum was diverse. Six tumours showed a mixture of cells with eosinophilic or clear cytoplasm in tubular, acinar and papillary architecture. One case was high grade with epithelioid, spindle cell and sarcomatoid areas. Another showed tubular, solid, and papillary areas and foci containing spindle cells reminiscent of mucinous tubular and spindle cell carcinoma. The third showed dyscohesive nests of large epithelioid and histiocytoid cells in a background of dense lymphoplasmacytic infiltrate. By immunohistochemistry, keratin AE1/AE3 was diffusely positive in three tumours, while CK7 strongly stained one tumour and another focally and weakly. CD10 and Pax8 were expressed by eight, AMACR and vimentin by seven, CA-IX by four and TFE3 and cathepsin K by two tumours. Of the two TFE3-positive tumours, one showed polysomy of chromosome 7 and the other of 17; they were VHL normal and diagnosed as unclassifiable RCC. Of the seven TFE3-negative tumours, three showed polysomy of 7/17 and VHL abnormality and were diagnosed as combined clear cell RCC/papillary RCC. One TFE3-negative tumour with normal 7/17 but LOH 3p (VHL abnormality) was diagnosed as clear cell RCC. One TFE3-negative tumour with polysomy 7/17 but normal VHL was diagnosed as papillary RCC, and two with normal chromosomes 7/17 and VHL gene were considered unclassifiable. As morphological features and IHC are heterogeneous, TRCC-like renal tumours can only be sub-classified accurately by multi-parameter molecular-genetic analysis.

To report the features of contrast-enhanced ultrasonography (CEUS) and computer tomography (CECT) of mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney. Six cases of MTSCC of the kidney were studied, and the literature was reviewed. Ultrasonography, CEUS, and CECT examinations were routinely performed before the operation. Histological analysis, including HE staining and immunohistochemistry, was performed with the envision method. The age of the patients ranged from 48 to 75 years (mean 55.5 years). One patient was male, and five were females. All six tumours exhibited an admixture of tubules, spindle cells, and mucinous stroma in variable proportions. CEUS and CECT showed enhancement of the lesions, but the enhancement was less than the adjacent renal parenchyma, leading to the diagnosis of hypovascular renal tumours. All patients were alive and well at the follow-up time of 17–73 months (mean 39.5 months) with CEUS and/or CECT at 3 months, 6 months, and 1 year and then annually thereafter following surgery. No metastases were detected. The CEUS and CECT findings of MTSCC were generally hypovascular and needed to be distinguished from other hypovascular renal tumours.

Mucinous tubular and spindle cell carcinoma of the kidney is a relatively rare pathologic entity that has recently been described in the World Health Organization 2004 renal cell carcinoma classification. We report two cases of mucinous tubular and spindle cell carcinoma in which contrast-enhanced ultrasound was used. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound 43:55–58, 2015

Clinical Practice Points � Mucinous tubular and spindle cell carcinoma (MTSCC) is an extremely rare primary carcinoma of the kidney that develops by malignant differentiation of the loop of Henle, is commonly confused with papillary renal cell carcinoma (RCC), and was classified in 2004 by the World Health Organization as a variant of RCC. � The tumor affects people of all ages, and the female to male ratio is 4:1. � We present a patient with an incidental finding of renal mass in the left kidney. � The patient underwent a transperitoneal radical nephrectomy. The immunohistochemical examination revealed MTSCC. Distant metastasis or local recurrences were not observed at the 36-month follow-up. � The differentiation of MTSCC from RCC and its subtype exhibiting sarcomatoid differentiation using immunohistochemical methods is considerably important to predict the prognosis. Widespread bone and lung metastases have been reported in the subtype exhibiting sarcomatoid differentiation. � Mucinous tubular and spindle cell carcinoma is generally a low grade tumor associated with good prognosis and its definitive treatment is surgical excision.

Objective. To dissect the characteristics of adrenal medullary hyperplasia (AMH) and share our experience of diagnosis and treatment of AMH.Methods. From 1999 to 2013, 12 cases of AMH have been pathologically diagnosed after operation in our hospital. The clinical characteristics, process of diagnosis, treatment, and prognosis during follow-up of all patients are summarized retrospectively.Results. Four cases were trended to be AMH and 6 cases were trended to be pheochromocytoma before operation; moreover, the other two patients were diagnosed accidentally. All patients, except for the patient with mucinous tubular and spindle cell carcinoma of left kidney by open surgery, experienced a smooth laparoscopic adrenalectomy, including 2 with radical nephrectomy, 10 of which experienced unilateral adrenalectomy, 1 was bilaterally partial adrenalectomy, and the remaining one was unilaterally complete removal and then 2/3 partially contralateral excision. After a medium follow-up of 6.5 years, it demonstrated a satisfactory outcome of 8 cured patients and 4 symptomatic improved patients.Conclusions. AMH presents a mimicking morphology and clinical manifestation with pheochromocytoma. Surgery could be the only effective choice for the treatment of AMH and showed a preferable prognosis after a quite long follow-up.

We report 4 distinctive renal epithelial neoplasms that are essentially identical at the morphologic and immunohistochemical levels and do not fit an accepted category in the existing classification of these lesions. The patients were all females, with ages ranging from 32 to 79 years (mean, 50 years). The tumors were well circumscribed and were composed of uniform, predominantly low cuboidal cells with eosinophilic, focally vacuolated cytoplasm. Tumor cells generally formed interconnecting tubules, with smaller areas of cordlike growth and spindling in a bubbly, myxoid stroma. All tumors were confined to the kidney, and all were immunoreactive for high-molecular-weight cytokeratin 34betaE12, cytokeratin 7, epithelial membrane antigen, and cytokeratin cocktail AE1/3. Only 1 tumor was focally immunoreactive for Ulex europaeus agglutinin. Ultrastructural study showed tumor cells forming tubular structures reminiscent of the loop of Henle or distal convoluted tubule. Follow-up in all 4 cases was benign. These distinctive tumors may be confused with aggressive sarcomatoid renal cell carcinomas because of their spindled morphology. The morphologic, immunohistochemical, and ultrastructural features of these lesions indicate differentiation toward distal nephron segments. Similar tumors probably have been reported among low-grade collecting duct carcinomas or tumors "possibly related to the loop of Henle."

Low grade mucinous tubular and spindle cell carcinoma of kidney was newly established as a distinct renal cell carcinoma in the World Health Organization (WHO) classification of 2004. Until now, less than 60 cases have been reported and the largest series represented approximately 15 patients with this type of tumor. Herein, we report a case of mucinous tubular and spindle cell carcinoma in a 63-year-old male presented with right flank pain which was diagnosed after nephrectomy. Pathologists should consider this diagnosis and its spectrum of histopathologic features in mind to ensure an accurate diagnosis.

A 33-year-old man was hospitalized for treatment of a left renal tumor. The radiological findings were consistent with those of a left renal cell carcinoma (RCC). Subsequently, a radical nephrectomy was carried out. Macroscopic examination showed that a well-demarcated tumor measuring 2.9 x 2.6 x 2.5 cm was present in the middle portion of the resected kidney. The cut surface of the tumor was grayish-white in color. Pathological examination of the resected specimen showed a mucinous tubular and spindle cell carcinoma of the kidney (MTSCC-K). MTSCC-K is a low-grade renal epithelial neoplasm that has recently been recognized as a specific entity in the World Health Organization 2004 classification of RCC. To our knowledge, 17 cases of MTSCC-K in Japan have been reported by Japanese investigators. To avoid administration of excessive adjuvant treatment to patients, pathologists and urologists should consider this newly recognized low-grade malignancy when diagnosing renal tumors.

Mucinous tubular and spindle cell carcinoma is a rare and newly described type of renal cell carcinoma (RCC) with a relatively indolent behaviour. We report a case of 53-year-old woman who had macroscopic hematuria and flank pain. A right radical nephrectomy was performed showing a well circumscribed tumour confined to the kidney and measuring 17cm. The histologic findings consisted of tightly packed, small, elongated tubules separated by pale mucinous stroma. The tumour cells were cuboidal to spindled with eosinophilic cytoplasm and lower nuclear grade. Tumour was immunoreactive for cytokeratin CK 7, CK19 and epithelial membrane antigen (EMA). The morphological and immunohistochemical features were consistent with mucinous tubular and spindle cell carcinoma of kidney.

Mucinous tubular and spindle cell carcinoma of the kidney is a relatively new and rare subtype of kidney tumors. Thus far, few reports have described imaging features of this tumor subtype. A 61-year

This report describes a renal tumor with an unusual histology in a 45-year-old woman. The tumor was white in color, different from usual renal cell carcinoma, and mainly consisted of variously shaped tubules formed by flat or cuboid cells within marked edematous stroma. Elaborated branching or tubules arranged in a papillary pattern with focal spindle-shaped cell proliferation were characteristic features. Immunohistochemical staining expressed diffusely positive for vimentin and S-100 protein, partially positive for cytokeratin and epithelial membrane antigen and negative for Leu-M1, Leu-7, CD34 and markers for muscle cells. Ultrastructural studies of the tumor cells showed adenocarcinoma-like characteristics. According to these histological, immunohistochemical and electron microscopy findings, it is suggested that this tumor be designated as unclassified renal cell carcinoma with histology mimicking lower-nephron nephrogenesis.

BACKGROUND Mucinous tubular and spindle cell carcinoma of the kidney is a newly established subtype in the World Health Organization classification. The tumor has a good prognosis, and its diagnosis is clinically important. However, there are no reports of its cytologic features. Here we report the cytologic findings of this rare tumor. CASE A 68-year-old female had left-sided abdominal pain, fatigue and hematuria. A large mass in the left kidney was removed. Histologically, the tumor was compatible with mucinous tubular and spindle cell carcinoma. Imprint cytologic examination revealed a large amount of tumor cells arranged in tubular, sheetlike and spindle structures. Some tumor cells showed clear cytoplasm. Nuclear atypia was mild, with occasional distinctive nucleoli. CONCLUSION The cytologic features of mucinous tubular and spindle cell carcinoma have a varied appearance. It should be included in the differential diagnosis to avoid overtreatment.

Objectives To assess the nature of a series of unusual low-grade mucin-producing tubulocystic renal cancers diagnosed at the Mayo Clinic since 1985. Methods We reviewed the clinical, radiologic, and pathologic features of 13 unusual low-grade renal carcinomas with features most suggestive of collecting duct origin. Results In 8 cases, the tumor was discovered incidentally. Presenting symptoms in the other 5 patients were similar to those of typical renal carcinoma. Imaging studies and angiography disclosed solid, cystic, or complex masses that were relatively avascular. Pathologic assessment revealed good circumscription, minimal hemorrhage and/or necrosis, minimal tendency to extend beyond the kidney, tubulocystic architecture, a fibrotic interface with adjacent normal renal parenchyma, low nuclear grade, and minimal mitotic activity. Mucin production was noted in all evaluable cases. All tumors expressed keratins AE1/AE3 and/or Cam 5.2. The tumors showed immunoreactivity to antibodies directed against keratin 34 β E12 (8 of 13 cases), and Ulex Europeus antigen I (6 of 10 cases). Follow-up ranged from 12 to 114 months (mean 62). No metastases occurred in 12 patients. One patient died of metastatic carcinoma morphologically identical to the primary renal neoplasm 46 months after his tumor had been misinterpreted as a benign condition. Conclusions We believe the tumors described in this article may be of collecting duct origin, representing the low-grade end of a spectrum of cancers arising in collecting duct epithelium.

A mucinous tubular and spindle cell carcinoma (MTSCC) is a rare and recently described kidney neoplasm with distal nephron differentiation. It can affect patients of all ages and is more prevalent among women. In this case report, we present a 50-year-old woman who had a renal mass, which was accidently discovered during an investigation for chronic anemia. The final diagnosis of MTSCC was made after the lesion was removed and a pathology work-up was performed. The clinical, pathological and imaging findings of this rare neoplasm are described in this report.

This article describes the features on sonography, computed tomography (CT) and magnetic resonance imaging (MRI) of mucinous tubular and spindle cell carcinoma of the kidney. Six pathologically proven cases of mucinous tubular and spindle cell carcinoma of the kidney were identified (5 females, 1 male); all patients underwent preoperative imaging. The mean age of the patients was 58.5 years. Thirteen imaging studies were available for review: 2 sonograms, 1 unenhanced CT scan, 5 contrast-enhanced CT scans, 1 unenhanced magnetic resonance imaging (MRI) examination, and 4 contrast-enhanced MRI examinations. Two abdominal radiologists evaluated all images retrospectively on a PACS workstation using a standardized data collection sheet until consensus was reached. All mucinous tubular and spindle cell carcinomas presented as well-marginated, small (mean 2.6 cm, range 1.9–3.2 cm) predominantly solid masses. No intratumoral fat or calcification was identified. Unenhanced CT and MRI appearances were variable as was the degree of enhancement following intravenous contrast material administration. There was no evidence of perinephric extension, renal vein involvement or metastatic disease in any of the cases. The radiological appearance of mucinous tubular and spindle cell carcinoma is diverse and therefore indistinguishable from the more common subtypes of renal cell carcinoma.

Tubulocystic carcinoma is a rare renal tumor with distinct characteristics which were recently described in details in three large series (1, 2, 3). Tubulocystic carcinomas of the kidney well circumscribed tumors. They are usually solitary and are composed of closely packed tubules and cysts separated by fibrous stroma and lined by a single layer of cuboidal cells with eosinophilic cytoplasm and prominent nucleoli, sometimes with a hobnail appearance. These tumors show a low but definite risk of metastasis, and it is therefore important to distinguish them from other benign and malignant renal lesions included in the differential diagnosis. Tubulocystic carcinoma was originally described as a subtype of collecting duct carcinoma (4). Carcinoma of the collecting duct of Bellini, first described by Pierre Masson (5) and characterized by a tubular or tubulopapillary growth pattern with high grade nuclei, follows an aggressive clinical course with a very poor prognosis. When tubulocystic carcinoma was first described, it was included in a series of 13 cases called “low grade collecting duct carcinoma” (4); these tumors feature a favorable clinical outcome distinct from high grade collecting duct carcinoma of the kidney. The entity “low grade collecting duct carcinoma” was later divided into two distinct subtypes, mucinous tubular and spindle cell carcinoma (6-8) and tubulocystic carcinoma (5). While mucinous tubular and spindle cell carcinoma is now recognized as a distinct subtype of renal cell carcinoma (RCC) in the World Health Organization classification system of renal tumors (WHO) (3), tubulocystic carcinoma is still being characterized (1, 2, 3, 9) and is not yet included in the current WHO classification system. Mounting morphologic, biologic, immunohistochemical, and molecular evidence supports that this tumor represents a unique subtype of RCC (1, 2, 3).