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Histiocytic sarcoma is a rare neoplasm of mature histiocytes with an aggressive clinical course and poor response to treatment. Primary gastric histiocytic sarcoma is rarer and just reported sporadically.Histiocytic sarcoma is a rare neoplasm of mature histiocytes with an aggressive clinical course and poor response to treatment. Primary gastric histiocytic sarcoma is rarer and just reported sporadically. A case of a 71-year-old female admitted with a one-year history of upper abdominal pain exacerbated after meals. After CT scans revealed a bulged mass at the lesser curvature of the gastric body, the patient underwent endoscopic submucosal dissection. Microscopically, non-cohesive neoplastic cells diffusely infiltrated lamina propria and submucosa, and diffusely expressed LCA, CD4, CD163, CD68 (KP1), Cyclin D1, Lysozyme, and Vimentin. PD-L1 (22CS) expression evaluated as CPS 60. The final pathological diagnosis was gastric histiocytic sarcoma. Subsequently, next-generation sequencing identified a nonsense mutation in exon 21 of NF1 gene [c.2446C > T (p.R816*)] and the TUBB3 gene amplification (copy number: 4.55). The patient refused further treatment and died of the tumor half a year later. This case broadens the spectrum of differential diagnosis of gastric cancer and emphasizes the value of immunohistochemical and molecular tests in the accurate diagnosis of histiocytic sarcoma. Furthermore, we performed literature review of 11 cases of gastric histiocytic sarcoma so as to strengthen the understanding of the clinicopathologic features, treatment, and prognosis., (© 2024. The Author(s) under exclusive licence to The Japanese Society for Clinical Molecular Morphology.)

Histiocytic sarcoma is an uncommon hematological malignancy. Its occurrence in the lung is very rare. Due to the small number of cases and the clinical and pathological features of the disease, the diagnosis can be challenging. Its optimal treatment is not yet known, in locally confined cases - depending on the location and size - surgical removal is part of complex oncotherapy. We report the case of a 52-year-old man with a tumor of central localization in the left lung. Pulmonectomy was performed. Histology verified histiocytic sarcoma of the lung. An overview of clinical features of the entity is presented in connection with our case report. Orv Heti. 2023; 164(34): 1350-1357.

A 7-year-old intact female domestic medium hair cat was examined at a veterinary clinic for a scabbed nodule over the right shoulder. Multiple nodules recurred at the same site after the first surgical excision, and a second surgical excision was performed. Histopathology demonstrated high-mitotic-rate neoplastic cells and therefore a histiocytic proliferative disease was initially suspected. The condition progressed rapidly within a 5-month period and the cat was euthanized due to sudden onset of severe dyspnea. Necropsy showed diffuse metastatic nodules in the lungs, confirming a histiocytic proliferative disease, with histiocytic sarcoma being the most likely differential diagnosis., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Histiocytic sarcoma is a relatively new disease category and the gastrointestinal origin is sporadic. We report a case of a 74-year-old woman who underwent chemotherapy and proximal gastrectomy for extremely rare, advanced gastric histiocytic sarcoma. The resected specimen was subjected to numerous immunostainings to meet the diagnostic criteria of histiocytic sarcoma and was positive for the histiocyte markers' cluster of differentiation 68 and lysozyme. The markers of Langerhans cells, follicular dendritic cells, and myelocyte were all negative. Six reports of surgical resection of histiocytic sarcoma originating in the stomach exist, including our case. We reviewed the clinical course and the histological and immunohistochemical diagnostic features of surgically resected gastric histiocytic sarcoma., (© 2021. Japanese Society of Gastroenterology.)

Localized histiocytic sarcoma may occur as a primary lesion in periarticular tissues of large appendicular joints. Treatment options for the primary lesion include radical surgical excision, radiation therapy (RT), or both, in combination with chemotherapy for potential systemic metastases. In an effort to better characterize the time to progression (TTP) following surgical vs non-surgical approaches for periarticular histiocytic sarcoma (PAHS), a contemporary European population of affected dogs was retrospectively surveyed. Medical records were queried for newly-diagnosed PAHS cases undergoing surgery (predominantly limb amputation) or RT followed by systemic chemotherapy. Of 49 dogs, 34 underwent RT and 15 underwent surgery. All dogs received adjuvant chemotherapy. There was no statistically significant difference in TTP or overall survival between groups. The median TTP was 336 days for the operated dogs and 217 days for the irradiated dogs (P = .117). The median overall survival time was 398 days for the operated dogs and 240 days for the irradiated dogs (P = .142). On multi-variable analysis, the variables significantly associated with an increased risk of both tumour progression and tumour-related death were regional lymph node and distant metastasis at admission. Survival and local control rates following RT may be comparable to radical resection. These data may better inform shared decision-making processes between multi-disciplinary care providers and owners., (© 2020 John Wiley & Sons Ltd.)

Background: Localized splenic histiocytic sarcoma (HS) in dogs is a poorly understood disease, and could have longer survival times than disseminated or hemophagocytic HS. Understanding the clinical behavior of localized splenic HS can refine treatment recommendations., Objective: To describe the clinical characteristics and outcomes of dogs with localized splenic HS., Animals: Fourteen client-owned dogs with histologically confirmed splenic HS that received splenectomy., Methods: Multi-institutional retrospective case series-medical records of dogs with splenic HS were reviewed. Dog signalment, clinicopathologic data, primary and adjuvant treatments, and outcomes were obtained. Survival data were calculated using Kaplan-Meier analysis. Dog variables such as age, weight, platelet counts were reported using descriptive statistics. The Cox proportional hazards regression method was used to determine whether potential risk factors (weight, age, albumin level, hematocrit, and platelet count) were associated with PFI., Results: Median survival time for the dogs in this study was 427 days. Twelve dogs received adjuvant lomustine-based chemotherapy. Five dogs (35.7%) were suspected or confirmed to have developed metastatic disease. Eleven dogs died of disease, 1 dog died of unrelated cause, and 2 dogs were alive at final follow-up., Conclusions and Clinical Significance: Histiocytic sarcoma in dogs can manifest as a localized form in the spleen. Dogs with localized splenic HS treated with surgery ± chemotherapy can experience survival times over a year., (© 2020 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Histiocytic sarcoma (HS) is a rare hematopoietic tumor that mainly involves extranodal sites, including the intestinal tract, skin, soft tissues and other organs. It is well known as an aggressive neoplasm that shows a poor response to therapy. However, a subset of patients with resectable disease has shown a favorable outcome with surgical treatment. Primary cutaneous HS is exceedingly rare and, to date, its long-term prognosis has thus not been well described. Here, we highlight two cases of primary cutaneous HS that showed long-term survival. Case 1 was a healthy 47-year-old woman who found a 12-mm tumor on her forehead. Case 2 was a 66-year-old woman, under follow up of a myxoid liposarcoma in her leg, who presented with a 25-mm tumor in her hypothenar eminence. Histologically, the tumors in both cases had a smooth outline with proliferating atypical tumor cells that showed histiocytic differentiation as revealed by immunohistochemistry with antibodies to CD68 (KP-1) and lysozyme in case 1; and CD68, lysozyme and CD163 in case 2. Tumor cells in case 1 had a monotonous appearance. After complete resection, cases 1 and 2 have survived for 10 and 4 years, respectively, without recurrence. To date, such patients are relatively long follow-up cases of survival from HS and highlight how a clear outline of the primary cutaneous HS tumor may be associated with its resectability and be an important factor in the assessment of its curability., (© 2020 Japanese Dermatological Association.)

Four-toed hedgehogs presented bloody stool and loss of appetite. Integumental masses were observed in two of the four cases. Intraabdominal masses were observed on radiographs and ultrasonography in the remaining two cases. The masses were surgically removed from all four cases. All samples were histologically and immunohistochemically consistent with histiocytic sarcoma (HS). At the time of surgery, 3 of 4 cases had grossly recognized metastatic/disseminated lesions. Survival time was 48 days, 64 days, and 113 days, respectively, and the remaining case is currently alive (at Day 207). The present report describes the clinical management and outcome of hedgehogs that were diagnosed with HS.

Histiocytic sarcoma is an extremely rare tumor in children. It may occur sporadically or in association with other hematological malignancies. It arises most commonly in the lymph nodes but may occur anywhere in the body and clinical presentation is usually with advanced disease. Following tissue diagnosis and staging, management is with chemotherapy though there are no standard regimes. Surgery has been used successfully for local control. This is the first description of the use of peritonectomy and hyperthermic intraperitoneal chemotherapy to treat histiocytic sarcoma. The 4-year-old patient has been disease free for 6 years., (© 2018 Wiley Periodicals, Inc.)

Histiocytic sarcoma (HS) is a rare hematopoietic neoplasm. We report a patient with HS treated with induction chemotherapy followed by curative surgery. A 50-year-old man was referred to our hospital because of a retroperitoneal tumor. A computed tomography scan revealed a bulky retroperitoneal mass, infiltrating the surrounding organ. An excisional biopsy confirmed the diagnosis of HS. The tumor shrunk after multidrug chemotherapy. However, positron emission tomography showed uptake of fludeoxyglucose in the residual tumor. He underwent right nephrectomy to remove the tumor. Pathological examination showed complete response. Surgery combined with induction chemotherapy may be an effective way to manage HS.

Background: Primary central nervous system (CNS) histiocytic sarcoma is an extremely rare lymphoproliferative disorder that affects the CNS and behaves aggressively. Only 27 cases of primary CNS histiocytic sarcoma have been reported. The paucity of literature on this entity has made diagnosis and treatment difficult both for the surgeon and the pathologist., Case Description: In this case of primary CNS histiocytic sarcoma, a middle-aged woman presented from an outside institution with a supposed cerebellar abscess. Intraoperative frozen pathology was initially interpreted as high-grade glioma; however, final pathology demonstrated histiocytic sarcoma., Conclusions: This report makes a significant contribution to the literature on this rare malignant disease by outlining a similar presentation among several cases and providing a thorough overview of existing criteria for diagnosis and management., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Histiocytic sarcoma (HS) is a rare malignant neoplasm showing morphologic and immunophenotypic features of histiocytes. Molecular characteristics of HS and fine-needle aspiration (FNA) criteria for its diagnosis have not been established., Methods: A case series of HS in 8 FNA samples from 6 patients was reviewed along with histopathologic and clinical data. Immunohistochemistry was performed on cell blocks (3 cases), core biopsies (5 cases), and surgical specimens (4 cases). Targeted-exome next-generation sequencing (NGS) was performed on surgical resection specimens in 4 cases., Results: Four patients had a known history of hematolymphoid malignancy. Cytomorphologic features included variably cellular smears composed of large epithelioid cells with reniform nuclei and abundant vacuolated cytoplasm, in an inflammatory background, with occasional cytophagocytosis and lymphoglandular bodies. Marked pleomorphism, multinucleated monster cells, and binucleated histiocytoid cells with partially overlapping, eccentrically placed nuclei resembling Pac-Man were common. Most cases expressed histiocytic markers CD68 (6 of 7 cases), CD163 (5 of 5 cases), and PU.1 (3 of 4 cases). In 3 cases, NGS analysis revealed alterations in lysine methyltransferase 2D (KMT2D)/mixed-lineage leukemia 2 (MLL2), a gene involved in chromatin regulation and previously implicated in the pathogenesis of follicular lymphoma., Conclusions: Although diagnosing HS with FNA alone is extremely challenging, the presence of pleomorphic and epithelioid large cells with binucleation and/or multinucleation in an inflammatory background should prompt the diagnosis of HS with judicious use of confirmatory histiocytic lineage markers. The detection of recurrent KMT2D/MLL2 alterations implicates epigenetic regulation in the pathogenesis of HS and supports the notion of transdifferentiation from a genetically similar but phenotypically distinct tumor of a different lineage. Cancer Cytopathol 2017;125:604-14. © 2017 American Cancer Society., (© 2017 American Cancer Society.)

Background: Histiocytic sarcomas (HS) frequently metastasise, most commonly to visceral sites, but also to regional lymph nodes. Nodal metastases are associated with a poorer prognosis. This retrospective study aimed to evaluate prognostic factors, including the effect of adjuvant chemotherapy, on survival in dogs with nodal, but not systemic, metastases from HS., Methods: Retrospective case series of 12 dogs with histologically diagnosed HS metastatic to lymph nodes treated with surgery with and without adjuvant chemotherapy., Results: All dogs had histological evidence of metastasis to lymph nodes, with no clinical evidence for metastasis to viscera. Eight dogs that received chemotherapy had a median estimated survival of 219 days (range 77-1638 days); 1- and 2-year estimated survival rates were 37.7%. Median survival time for 4 dogs with nodal metastases that did not receive chemotherapy was 57 days (range 39-136 days) with none alive 1 year after surgery CONCLUSION: Survival for dogs with only regional nodal metastases from HS appeared to be improved by adjuvant chemotherapy., (© 2017 Australian Veterinary Association.)

No reports have been published to date regarding primary gastric granulocyte colony-stimulating factor (G-CSF)-producing histiocytic sarcoma. We encountered a case of primary gastric histiocytic sarcoma that also fulfilled the criteria for a G-CSF-producing tumor. A 75-year-old man was diagnosed with gastric cancer with poorly differentiated adenocarcinoma. The patient's white blood cell count was elevated to 20,700/μL, and the G-CSF level was elevated to 380 pg/mL. A computed tomography scan showed hepatic infiltration; therefore, a preoperative diagnosis of T4 (liver) N2H0M0 cStage IV gastric cancer was made, and surgery was performed. No. 11d lymphatic metastasis was noted, resulting in invasion of the pancreatic tail, and combined resection of the liver, pancreas, and spleen was conducted with complete gastrectomy. The results of hematoxylin-eosin and immunohistochemical staining were subsequently assessed. On discharge, the G-CSF level had fallen to 22.7 pg/mL. Currently, the patient is still alive and has experienced no recurrence approximately 4 years after the operation.

We report a 16-year-old male with histiocytic sarcoma (HS) originating in the lung. Partial resection of the lung was performed for a 3-cm mass with a clear boundary detected in the right inferior pulmonary lobe on a health checkup. Histologically, the tumor infiltrated into the surrounding tissue, and was comprised of spindle cells, mainly, and foam cells accompanied by mild nuclear atypia. The tumor cells were immunohistochemically positive for CD68 and CD163, indicating histiocytic lineage and the MIB-1-positive rate was low. Spindle cell morphology of HS is quite rare and only 3 cases of pulmonary HS have previously been reported.

An 80-year-old man was admitted with anorexia, a high fever and general icterus. Laboratory examinations revealed remarkable inflammation and elevation of liver/biliary enzymes. Computed tomography (CT) showed a high-density lesion in the bile duct, and endoscopic retrograde cholangiopancreatography (ERCP) disclosed an oval filling defect mimicking choledocholithiasis. Plastic stents were inserted to treat the acute cholangitis; however, the patient's symptoms recurred. An erythematous hypervascular mass obtained with a balloon catheter contained numerous pleomorphic histiocytic cells with eosinophilic cytoplasm, remarkable anisonucleosis and occasional mitoses. A diagnosis of histiocytic sarcoma (HS) was made based on the results of intensive immunohistochemistry. Monoclonal rearrangement of the IGH and TCRG genes, IGH split and IGH/BCL2 fusion was negative, although polysomy 8, 14, and 18 was detected. The patient was treated conservatively and died of the disease 20 months after the initial diagnosis. To the best of our knowledge, this is the first case of bile duct HS. This case, which involved numerical alterations of chromosomes, presented with CT and ERCP findings similar to those of choledocholithiasis.

Histiocytic sarcoma is a rare malignancy with only 10 reports confirmed primarily involving the CNS. The diagnosis is dependent on the finding of malignant cells with histiocytic morphology and immunophenotype. The authors report a case of pathologically proven HS of the CNS. A 16-year-old boy presented with headaches, emesis, and altered sensorium. Noncontrast head CT scanning demonstrated a left parietal mass consistent with a tumor. Surgery was undertaken. Intraoperative findings revealed green-yellow exudates consistent with an abscess. Cultures were obtained and broad-spectrum antibiotics were started. The patient subsequently underwent multiple surgical procedures, including drainage and debulking of abscesses and hemicraniectomy. Two months after initial presentation, the patient's diagnosis of histiocytic sarcoma was confirmed. Pathological examination demonstrated necrotizing inflammation with preponderant neutrophil infiltration, variably atypical mononuclear and multinucleate histiocytes, and numerous mitoses. Additional immunohistochemistry studies confirmed immunoreactivity for CD68, CD45, CD45RO, and CD15 and were negative for CD3, CD20, melanoma cocktail, CD30, CD1a, CD34, HMB-45, and melan-A. Once the diagnosis of histiocytic sarcoma was confirmed, antibiotics were stopped and radiation therapy was undertaken. Despite treatment, the patient's neurological status continued to decline and the patient died 126 days after initial presentation. This case represents a rare confirmed example of CNS histiocytic sarcoma. A profound inflammatory infiltrate seen on pathology and green exudates seen intraoperatively make the condition difficult to distinguish from an abscess. Immunohistochemistry showing a histiocytic origin and negative for myeloid, dendritic, or other lymphoid markers is essential for the diagnosis. Further research is needed to establish consensus on treatment.

Histiocytic sarcoma is a rare hematologic malignant neoplasia originating from histiocytic or dendritic cell clones. The lesions may be in nodal or extranodal sites, most commonly in the gastrointestinal tract. A small number of cases presents as unique cutaneous lesions. The definitive diagnosis is made by positivity for the immunohistochemical markers CD163, CD68, CD4 and lysozyme. The treatment is controversial, often with combined systemic chemotherapy. This is a case of cutaneous histiocytic sarcoma in an 82-year-old patient presenting two nodular lesions in the breast and right arm which were treated with simple excision and multidisciplinary follow-up, avoiding aggressive management and exhaustive investigations. Although most studies report aggressive evolution, the patient had good and stable clinical status during the twelve-month follow-up period.

Histiocytic sarcoma (HS) is a rare malignant neoplasm that originates from a histiocytic hematopoietic lineage characterized by histiocytic differentiation and its corresponding immunophenotypic features. We herein reported a case of primary HS of the stomach which was confirmed through histopathologic examination and immunohistochemical staining. A 52-year-old woman presented with progressive difficulty in feeding and dull pain in the epigastric region. Gastroscopy, endoscopic ultrasonography, double contrast examination, and computed tomography revealed a mass located on the posterior wall of fundus and lesser curvature of the stomach. Microscopically, the cytoplasm of the tumor cells was abundant and eosinophilic. Immunohistochemical staining revealed that the tumor cells were positive for CD45RO and CD68. It is difficult to differentiate HS of stomach from other gastric malignancies by radiological evaluation alone. However, HS may be considered when a protruding and ulcerated mass in stomach shows heterogeneous hypervascular features. To the best of our knowledge, this is the first report in English language literature that emphasizes the imaging findings of human gastric HS.

A 67-year-old Japanese female was followed up due to prolonged idiopathic thrombocytopenia with non-response to steroid therapy for 4 years, but recent progressive pancytopenia, hypo-albuminemia, and hypo-γ-globulinemia were presented. An abdominal CT scan revealed heterogeneously enhanced splenomegaly without any nodular lesions. A splenectomy was performed, and gross examination showed markedly hyperemic red pulp, weighing 760 g, accompanied by multiple foci of peripheral anemic infarction. Surprisingly, microscopic findings exhibited a diffuse proliferation of medium-sized to large tumor cells having pleomorphic nuclei, prominent nucleoli, and abundant eosinophilic cytoplasm, predominantly within the sinuses and cords of the red pulp, which occasionally displayed conspicuous hemophagocytosis and vascular permeation. In immunohistochemistry, these atypical cells were specifically positive for CD68 (KP-1), CD163, and lysozyme, which was consistent with histiocytic sarcoma (HS) of the spleen. Subsequently, section from the aspiration of bone marrow showed infiltration of the neoplastic cells associated with erythrophagocytosis 2 months after the operation, but never before it. Therefore, primary splenic HS presenting with secondary bone marrow involvement was conclusively diagnosed. Since early diagnosis and treatment are necessary for the HS patients with poor outcomes, splenic HS should be considered as a differential diagnosis in cases with chronic thrombocytopenia and splenomegaly., Virtual Slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1009474924812827.

Background: Splenic fibrohistiocytic nodules (SFHN) are commonly diagnosed. It is suspected that these represent a heterogeneous group of malignant and nonmalignant diseases, separation of which could improve the ability of clinicians to prognosticate for dogs., Hypothesis/objectives: Immunohistochemistry will differentiate histologic diagnoses within the group of SFHN; survival after splenectomy is associated with those histologic types., Animals: Thirty-two dogs with SFHN treated by or under direction from veterinary oncologists., Methods: Retrospective case record analysis from dogs followed from splenectomy until death. Clinical, histopathologic, and immunohistochemistry data analyzed for an association with survival time., Results: Thirty-two dogs had SFHN; grade 1 (2 dogs), grade 2 (9 dogs), and grade 3 (lymphoid percentage <40%; 21 dogs). Twenty-two dogs died, 10 were censored (9 alive median of 883 days after splenectomy). Median overall survival was 387 days, and grade 3 SFHN was negatively [corrected] associated with survival time as previously reported (P < .001). Of 31 available samples, dogs had diseases reclassified as nodular hyperplasia (13; 8 complex, 5 lymphoid including 2 marginal zone), lymphoma (4; 2 marginal zone lymphoma, 1 high grade B-cell lymphoma, and 1 marginal zone transitional to high grade B-cell lymphoma), 8 stromal sarcomas, and 6 histiocytic sarcomas. Dogs with histiocytic sarcoma had worse survival (median 74 days) than dogs with other diseases., Conclusions and Clinical Importance: Splenic histiocytic sarcoma is an aggressive disease; however, some dogs with stromal sarcomas had long survival times. The term SFHN is no longer warranted for this group of disorders., (Copyright © 2012 by the American College of Veterinary Internal Medicine.)

The authors report on a case of histiocytic sarcoma (HS) in a pediatric patient presenting with a solitary tumor in the cerebellum, with the aim of providing insight into primary HS in the CNS, which is especially rare. A 17-month-old Japanese girl presented with a 2-week history of progressive gait disturbance. Brain MRI revealed a 4.7 × 4.3 × 4.3-cm well-demarcated solitary mass in the right hemisphere of the cerebellum, initially suggestive of medulloblastoma, ependymoma, or anaplastic astrocytoma. On intraoperative inspection the cerebellar tumor showed intensive dural attachment and was subtotally removed. Histological and immunohistochemical findings were consistent with HS. The patient subsequently received chemotherapy, and her preoperative neurological symptoms improved. Primary HS in the CNS usually demonstrates an aggressive clinical course and is currently considered to have a poor prognosis. The possibility of this rare tumor should be included in the differential diagnosis of localized cerebellar tumors in the pediatric age group.

We report a rare case of extranodal histiocytic sarcoma with multifocal gastrointestinal tract involvement, which has not been documented in the literature so far. A diagnosis of interdigitating dendritic cell/ histiocytic sarcoma was made on the preoperative gastric biopsy. Computed tomography scan revealed multifocal, circumferential gastrointestinal wall thickening involving the stomach and jejunal loops. Patient underwent distal gastrectomy with extended D1 dissection and proximal jejunal resection with gastrojejunostomy. Immunohistochemistry profile of both the gastric and jejunal tumors was similar to the preoperative gastric biopsy. The histiocytic origin of the tumor was confirmed by positive reaction of the tumor cells for CD 163. She received four cycles of CHOP chemotherapy, and is free of disease three years, following surgery.

This article describes a rare malignant spinal tumor successfully treated with total en bloc spondylectomy via a posterior approach. The purpose of this study was to emphasize the occurrence of primary histiocytic sarcoma in the lumbar spine. Histiocytic sarcomas are rare, malignant neoplasms of the lymphohematopoietic system that usually occur in the skin, lymph nodes, and intestinal tracts. Primary spinal column histiocytic sarcoma is rare. To the authors' knowledge, no reports have been published of treating this tumor with total en bloc spondylectomy.A 27-year-old woman presented with a 2-month history of intermittent low back pain and right lower extremity pain. Magnetic resonance imaging and computed tomography (CT) revealed a lumbar vertebra tumor. Positron emission tomography/CT showed focal accumulation in the tumor site. The patient was diagnosed with a histiocytic sarcoma based on biopsy findings and underwent total en bloc spondylectomy of L3 and reconstruction via a posterior approach. The patient maintained normal neurologic function, and the pain was lessened. No major complications occurred. No radiotherapy or chemotherapy was administered postoperatively, and no local tumor recurrence or distant metastases existed at 2-year follow-up.The diagnosis of histiocytic sarcoma relies predominantly on the verification of histiocytic lineage and the exclusion of other, poorly differentiated, large-cell malignancies by immunohistochemical stain. Total en bloc spondylectomy at L3 via a posterior approach can be performed safely and is an important approach in the treatment of selected spinal tumors., (Copyright 2012, SLACK Incorporated.)

A 9-year-old spayed female domestic shorthair cat presented with a skin lesion of the left tarsus. The lesion was biopsied and, based on the microscopic appearance and immunohistochemical characteristics, histiocytic sarcoma was diagnosed. Amputation was performed with improved demeanor seen postoperatively. However, between 44 and 60 days following the surgery, relapse of skin lesions appeared in multiple locations, including at the previous amputation site, and euthanasia was elected. This is the first report of a histiocytic sarcoma treated with amputation in a cat.

Histiocytic sarcoma (HS) is a malignant neoplasm showing the morphological and immunophenotypic features of mature histiocytes. Reported herein is a case of HS of the parotid gland region. A 53-year-old woman noticed a swelling of the right preauricular area. Preoperative fine needle aspiration cytology showed an admixture of pleomorphic atypical cells and mature lymphocytes. She underwent total parotidectomy. Grossly, the tumor was located at the parotid gland to subcutaneous tissue, and showed infiltrative growth with massive necrosis and hemorrhage. Microscopically, the tumor was composed of marked pleomorphic cells with eosinophilic cytoplasm. Bizarre multinuclear giant cells were scattered and intermingled. Tumor cells were positive for CD68 (KP-1 and PG-M1), CD163, S-100 protein, CD1a, CD4 and CD31, but negative for CD3, CD20, CD21, CD79a, DEC205 and langerin, immunohistochemically. Monoclonal proliferation of B cells was not confirmed on polymerase chain reaction for IgH. The patient had recurrent lesions in the pelvis and stomach 5 months after parotidectomy and died of the disease 10 months after the operation., (© 2011 The Authors. Pathology International © 2011 Japanese Society of Pathology and Blackwell Publishing Asia Pty Ltd.)

We report the unusual case of a three-year-old girl which presented since birth a pigmented tumor of the left side 0.5cm in diameter. Surgical removal was decided given the hypothesis of a congenital naevo-cellular naevus. The histological study ended with the diagnosis of plexiform fibrohistiocytic tumor (PFHT). Two other congenital PFHT have been reported until now. PFHT is a rare mesenchymal neoplasm of intermediate malignancy, first reported by Enzinger and Zhang in 1988 which may be difficult to diagnose, because of its low frequency, particulary in congenital cases. It is important to distinguish it from others childhood cutaneous tumors (particulary plexiform neurofibroma, cellular neurothekeoma, infantile myofibromatosis, and fibrous hamartoma). The tumor has a high local recurrence rate and complete surgical resection of the tumor, with wider margins, is required., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

We present a 62-year-old Chinese woman with histiocytic sarcoma (HS) and diffuse large B cell lymphoma (DLBL) located in the stomach. HS showed abundant eosinophilic cytoplasm with large, pleomorphic nuclei. Tumor giant and multinucleated cells were also prominent. Hemophagocytosis was common in the neoplastic cells. These cells were positive for CD68, CD45RO, and leukocyte common antigen (LCA), partly positive for S-100 and lysozyme, and negative for CD3, CD5, CD20, Pax-5, CD79a, CD1a, CD21, CD35, CD34, myeloperoxidase, HMB45 and cytokeratin (CK). These cells invaded the submucosa, muscularis mucosa, and serosa. DLBL was located in the mucosa and engulfed the covering epithelium and gland. The nuclei of tumor cells were medium-to-large in size, being ≥twice the size of normal lymphocytes. They were diffusely positive for CD20, Pax-5, and LCA, partly positive for vimentin, CD79a, CD10, CD30, CD15, and epithelial membrane antigen, and negative for S-100, CD1a, CD21, CD5, cyclin D1, CD23, CD35, HMB45, and CD68. Both types of tumor cell were positive for Oct-2, Bcl-2, and Bcl-6. These results suggest that HS may have shared a common clonal origin with DLBL, or may have transdifferentiated from DLBL The patient refused further chemotherapy, and died 7 months after surgical resection.

Intramedullary primary central nervous system lymphoma (PCNSL) is a rare central nervous system (CNS) malignancy affecting mostly the brain, but it may also involve the leptomeninges, eyes, and spinal cord. A 71-year-old woman presented with back pain and progressive unilateral lower extremity weakness owing to an intramedullary primary histiocytic sarcoma of the spine, a rare PCNSL subtype. To the authors' knowledge, this is the first case of an intramedullary PCNSL caused by histiocytic sarcoma., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Histiocytic sarcoma (HS) is an extremely rare true histiocytic malignancy. We report a case of HS arising from thyroid gland in a 69 year-old man. Following subtotal thyroidectomy, a histopathologic, immunohistologic, and genotypic examination revealed HS. This tumor was composed of large spindle or round epithelioid cells with abundant eosinophilic cytoplasm. The neoplastic cells were positive for macrophage-associated antigen CD68, CD163, and lysozymes, as well as CD45, HLA- DR, DP, DQ, and S100, most consistent with a diagnosis of HS. The BIOMED-2 multiplex PCR analysis showed polyclonal B- and T-cell populations. To our knowledge, this is the first report of a rare entity HS involving thyroid gland using a comprehensive immunophenotyping panel including CD163 as well as molecular studies to establish the true histiocytic nature of these lesions.

Objective: To study the morphologic features, immunophenotypes, differential diagnoses and prognosis of histiocytic sarcoma (HS)., Methods: The clinical and pathologic findings of 6 cases of HS were reviewed. Immunohistochemical assay (Elivision staining) was also performed. Follow-up information was available in 4 patients., Results: There were altogether 3 males and 3 females. The age of patients ranged from 12 to 81 years old (median = 54.6 years). The sites of involvement included lymph node (number = 2 cases) and skin or soft tissue (number = 4 cases). The tumor was composed of sheets of large epithelioid cells with abundant eosinophilic cytoplasm, oval to irregular nuclei, vesicular chromatin and large nucleoli. Binucleated form was not uncommon. Two of the cases showed increased pleomorphism with multinucleated tumor giant cell formation. Focal cytoplasmic with foamy appearance was identified in 3 cases. One case demonstrated foci of spindly sarcomatoid appearance. Hemophagocytosis was identified in 2 cases. Mitotic figures were readily identified. The tumor cells were often accompanied by various numbers of inflammatory cells. Immunohistochemical study showed that all cases were diffusely positive for leukocyte common antigen, CD4, CD68 and CD163. Four of the 5 cases studied also expressed lysozyme. Amongst the 4 patients with follow-up information available, 3 died of the disease at 6 to 11 months interval after diagnosis. One patient, whose lesion was localized at the skin and soft tissue, survived for 3 years, with no evidence of tumor recurrence., Conclusions: Accurate diagnosis of the HS is based on the combination of morphologic examination and immunohistochemical assay. HS often presents with clinically advanced disease and pursues an aggressive clinical course, with a poor response to therapy. However, a subset of cases presenting with clinically localized lesion may carry a relatively favorable long-term outcome.

Case Description: An 11-year-old neutered female domestic longhair cat was evaluated because of a 1-week history of progressive dyspnea, signs of depression, and loss of appetite. A histiocytic sarcoma had been excised from the mammary gland 6 weeks earlier., Clinical Findings: Physical examination findings were consistent with pleural effusion, and thoracic and abdominal radiography and ultrasonography revealed pleural effusion, a thoracic mass involving the aorta and pulmonary artery, and a caudal abdominal mass that most likely represented enlarged iliac lymph nodes. Cytologic examination of the pleural fluid and fine-needle aspirates from the iliac and right popliteal lymph nodes revealed abundant cells with neoplastic characteristics of indeterminate origin. The clinical diagnosis was generalized malignant neoplasia., Treatment and Outcome: Pleural drainage was necessary every 5 to 6 days. Exploratory thoracotomy and biopsy of the mass were recommended for better characterization of the thoracic disease. Simultaneously, palliative treatment by advancement of the omentum into the thorax was performed. A final diagnosis of disseminated histiocytic sarcoma was made, and treatment with doxorubicin was begun after surgery. During the 13 months after surgery, the cat was free from signs of respiratory tract disease and had normal activity levels with good exercise tolerance. Fifteen months after surgery, the cat's clinical condition worsened and the cat died., Clinical Relevance: Findings suggested that thoracic omentalization may be considered for palliative treatment of cats with refractory neoplastic pleural effusion when frequent thoracocentesis is necessary and other treatments are not suitable.

A 10-year-old spayed female Golden Retriever was admitted with chronic lameness of the right hind limb. A tibial plateau leveling osteotomy (TPLO) had been performed on this leg approximately three years previously. A progressively growing soft tissue mass, affecting the right stifle, previously treated with TPLO was biopsied and found to be a histiocytic sarcoma. Previously proposed links between the development of neoplasia in the stifle region and the presence of chronic synovitis, osteotomy, orthopaedic implants, and specifically the Slocum TPLO plate, are briefly discussed.

A 9-year-old male Rottweiler was presented to the Veterinary Medical Hospital Montenegro, Porto, Portugal with a large mass medial to the left stifle and radiographic signs of bone lysis involving the proximal tibia, fibula, and distal femur. A fine-needle aspiration was obtained from left popliteal lymph node, which was markedly enlarged. Cytologic examination revealed a highly cellular sample consisting of pleomorphic cells with marked anisocytosis and anisokaryosis and other criteria of malignancy. Some cells contained intracytoplasmic, granular, dark brown material, consistent with hemosiderin. Histologic evaluation of the surgically-excised lymph node revealed a neoplastic proliferation of histiocytic cells, with marked pleomorphism; occasional cells were erythrophagocytic. Mitotic figures were frequently observed, and many were atypical. Histologic findings were consistent with malignant histiocytosis. Necropsy examination confirmed the diagnosis of malignant histiocytosis with systemic involvement affecting most organs examined. This case of malignant histiocytosis case had an atypical clinical presentation, mimicking a musculoskeletal disorder. It underlines the importance of cytology as a simple, inexpensive, rapid and noninvasive complementary exam in routine clinical practice that can permit early diagnosis of the disease and timely selection of the most adequate therapy.

Three flat-coated retrievers with a regenerative anaemia were examined. They were hypoproteinaemic suggesting that the anaemia might be due to blood loss, but it was not possible to identify a site of haemorrhage. All three had splenomegaly with splenic abnormalities apparent on ultrasonography. Ultimately all three animals were shown to have a histiocytic sarcoma involving the spleen and other tissues. A fourth flat-coated retriever with anaemia, hypoproteinaemia and an abdominal mass was also diagnosed with a histiocytic sarcoma of the spleen following splenectomy. It is postulated that the dogs' anaemia was due to erythrophagocytosis, either directly by neoplastic cells or by reactive macrophages.

Proliferations of Langerhans cells can be histologically divided into cytologically benign Langerhans cell proliferations, which include the clinical syndromes of Langerhans cell histiocytosis, and cytologically malignant Langerhans cell sarcoma. We report a Langerhans cell sarcoma in a 33-year-old male that arose on the posterior thigh with subsequent regional lymph node involvement. Conventional microscopic, immunohistochemical, and ultrastructural analysis confirmed Langerhans cell differentiation. Aberrant CD31 expression, similar to that described previously in Langerhans cell histiocytosis, was prominent in this tumor, possibly enhancing its migratory capabilities.

In 13 patients with primary malignant bone tumors (10 Ewing's sarcoma, 1 parosteal osteosarcoma, 1 adamantinoma recurrence, and 1 MFH) local therapy was performed as intraoperative extracorporeal irradiation and replantation (IEIR) of the involved bone segment (5 tibia, 2 femur, and 6 pelvis). Of the 13 patients (69%), 9 are alive at the time of the follow-up (5 CDF, 4 AWM(treated)) and 4 patients died of disease (DOD). Up to now during the follow-up of 32 months (6-57), no local recurrence was observed in the replanted bone segments. The complication rate was very high (18 complications in 11 of the 13 patients, including 6 cases with complication V degrees according to Ruggieri with loss of the reconstruction). The typical complication is severe local infection necessitating removal of the replant. In cases of mechanical failure, the replanted segment could mostly be preserved by surgical revision and autologous bone grafting. If serious complications can be managed or avoided, functional results can be achieved. IEIR must be seen as an extraordinary reconstruction procedure in cases where established procedures such as endoprosthesis, biological reconstructions, or rotationplasties cannot be used or are refused by the patient.

Malignant fibrous histiocytoma is the most common soft tissue sarcoma in adults with the majority of cases that occur in patients between 50-70 years and most of cases occurs in male. Seventy percent originate from extremities. Primary MFH involving the central nervous system is a rare occurrence with most cases originating from the dura or leptomeninges. A case of primary intracranial malignant fibrous histiocytoma in a 60-year-old man is presented. The tumor was successfully excised and the patient remained well at follow-up of 12 months. The clinical features of this case and the therapeutic prognosis of 24 cases reported previously in the literature were reviewed.

Objective: To observe the efficacy and side effects of allogeneic bone marrow transplantation (allo-BMT) in the treatment of malignant histiocytosis (MH)., Methods: After conditioning with chemotherapy and total body irradiation, HLA-A, B, DR, DQ compatible allo-BMT was performed in a patient with MH., Results: DNA fingerprinting showed engraftment on day 22, bone marrow aspiration showed hypercellularity on day 50, and no abnormal cell was found. The patient developed acute graft-versus-host disease ( II degrees) on day 40 and herpes zoster 6 months post-transplantation, and the patient has survived disease-freely for 24 months after allo-BMT., Conclusion: This is the first report of treatment of MH with allo-BMT in China, showing that allo-BMT may significantly prolong the survival of MH.

The direct transnasal transsphenoidal approach to the pituitary fossa has been used in our unit since 1987. We describe the procedure and report its use in 48 patients with pituitary lesions. Successful access to the pituitary fossa was made in 46 out of 50 operations (92%). In two cases, repeat transnasal exploration was successfully performed for recurrent tumour 3 and 5 years following an initial trans-nasal exploration. This approach is straightforward, quick and does not require dissection of nasal mucosa or removal of septal cartilage. There was a 5.8% rate of major post-operative complications, and this compares favourably with other routes of access to the pituitary fossa. No long-term nasal, septal or dental complications have occurred, such as may happen with the other routes to the sphenoid sinus and pituitary fossa.

Two young females were admitted one by one because of peculiar skin eruptions suggesting mosquito-allergy and severe pancytopenia with normo-hypercellular bone marrow. The outcome of the first case was fatal on account of severe pancytopenia, immune deficiency and marked jaundice 14 months after the initial pancytopenic episode. In the post-mortem examination, HMR (histiocytic medullary reticulosis) was highly suggestive since hepatosplenomegaly with increase of Kupffer cells and large histiocytes including some atypical cells were detected. The second patient was treated with splenectomy because the past treatment were unsatisfactory in the first case and another cases in literatures. After the operation, the patient sustained almost normal blood cell level for 11 months without any treatment. As for the histopathological findings of resected spleen and lymphnodes, some erythrophagocytic mature histiocytes were found, but no atypical cells was detected. The relationship with pancytopenia, mosquito-allergy and HMR was discussed on the two cases and literatures.