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Synovial sarcoma (SS) is a rare and malignant mesenchymal neoplasm. We report a case of a 16-year-old Chinese female diagnosed with biphasic synovial sarcoma. The imaging features, surgical procedures and pathological results of the lesion were described in detail. Additionally, we conducted a review of the literature on synovial sarcoma of the thigh over the past 2 decades, identifying a total of 25 relevant case reports and summarizing the characteristics of these cases. Synovial sarcoma has a high degree of malignancy, with a high recurrence and metastasis rate, and a 5-year survival rate of 36%–76% and a 10-year survival rate of 20%–63%, so early detection of the lesion and preoperative differential diagnosis are of paramount importance in the treatment of patients. [ABSTRACT FROM AUTHOR]

Cutaneous malignancies of the head and neck are common; however, superficial sarcomas of the head and neck are relatively rare. We present a 71-year-old unhoused gentleman with challenging access to medical care and poor health literacy who presented with a large, isolated, pedunculated mass of the left auricular helix. Preoperative biopsy was compatible with pleomorphic dermal sarcoma (PDS). The patient subsequently underwent definitive surgical resection with partial auriculectomy and bilateral advancement flap closure. Final pathology confirmed the diagnosis of PDS. Given the rarity of PDS of the ear, we describe a challenging case presentation, diagnosis, and management in an unhoused patient. [ABSTRACT FROM AUTHOR]

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Solitary fibrous tumors are rare and typically benign fibroblastic neoplasms with a mean age of onset ranging from 60 to 70 years. Solitary fibrous tumors may arise anywhere within the body, however the pleura is the most common site of origin for these tumors, with approximately 30% of tumors arising from the pleura. In this report we highlight the case of a 62-year-old woman who presented with gradually progressive left sided chest pain that was eventually diagnosed as a pleural SFT. We highlight the appearance of solitary fibrous tumor of the pleura on computed tomography and positron emission tomography imaging, as well as providing detailed cinematic rendering images of these rare neoplasms.

Solitary fibrous tumor (SFT) arising from adult mesenchymal stem cells is an uncommon vascular tumor of pelvic cavity. While initially thought to be confined to the pleura, pericardium, or peritoneum, recent studies have revealed that SFTs can develop in different areas of the body. Typically, SFTs grow slowly and may not present noticeable symptoms. In this 2 case study, we describe the clinical situation of a 46-year-old female patient and 68 years old male patient who complained of persistent pelvic pain and urinary symptoms respectively. Imaging tests revealed solitary fibrous tumor in the pelvic cavity which was confirmed on histopathology, an unusual location for this type of tumor. This case reports focusses on importance of early recognition and treatment in dealing with this rare tumor.

Introduction The present study describes a case of an intracranial solitary fibrous tumor (iSFT) concurrent with meningioma in different anatomical regions.

• Aggressive angiomyxoma is a rare mesenchymal myxoid neoplasm in women at reproductive age. • The main treatment is surgery, but local recurrence rate is high. • Careful preoperative evaluation and long-term follow-up are important. Aggressive angiomyxoma is an uncommon mesenchymal neoplasm characterized by a high recurrence rate, usually observed in the lower genital tract of women during their reproductive age. Seventeen cases of aggressive angiomyxoma confirmed by pathology from January 2007 to December 2021 in Beijing Chao-yang Hospital were included. We collected clinical data and summarized the clinical and immunohistochemical features. All seventeen included patients were females, aged between 23 and 57 years (mean, 37.7 years; median, 42 years). Fourteen patients were newly diagnosed and three were recurrent. The tumors were located in vulva (58.8 %), vagina (23.5 %), buttock (11.8 %), and cervix (5.9 %). The tumors size were 2 to 15 cm in greatest dimension (mean 8 ± 4.4 cm, median 6 cm). Follow-up data was available for nine patients, which ranged from 25 to 124 months (mean, 82 months; median, 80 months). At the end of follow-up, no other recurrence or metastasis was reported. Immunohistochemical analysis showed immunoreactive for estrogen (10/11) and progesterone (8/11) receptor, desmin (6/8), smooth muscle actin (4/10), and vimentin (4/4), S-100 (1/8) and CD34 (1/7). The Ki67 level was less than 5 % in five cases. AAM is a hormone-sensitive, distinct rare mesenchymal neoplasm with high incidence of local recurrence. Surgery is the preferred treatment, with complete resection being an essential prerequisite for minimizing the risk of recurrence. [ABSTRACT FROM AUTHOR]

There is a diverse group of non-gastrointestinal stromal tumor (GIST), mesenchymal neoplasms of the gastrointestinal (GI) tract that demonstrate characteristic pathology and histogenesis as well as variable imaging findings and biological behavior. Recent advancements in tumor genetics have unveiled specific abnormalities associated with certain tumors, influencing their molecular pathogenesis, biology, response to treatment, and prognosis. Notably, giant fibrovascular polyps of the esophagus, identified through MDM2 gene amplifications, are now classified as liposarcomas. Some tumors exhibit distinctive patterns of disease distribution. Glomus tumors and plexiform fibromyxomas exhibit a pronounced affinity for the gastric antrum. In contrast, smooth muscle tumors within the GI tract are predominantly found in the esophagus and colorectum, surpassing the incidence of GISTs in these locations. Surgical resection suffices for symptomatic benign tumors; multimodality treatment may be necessary for frank sarcomas. This article aims to elucidate the cross-sectional imaging findings associated with a wide spectrum of these tumors, providing insights that align with their histopathological features. [ABSTRACT FROM AUTHOR]

Report _Case Presentation _Photo Vignette _Letter Authors declare that the contents of this article are their own original unpublished findings. Title: Primary cutaneous perivascular epithelioid cell tumors: two cases and a review of the literature Authors: Jennifer Wong1 DO, Jason Mammino2 DO, Jennifer Seyffert3 DO, Kristen Schmits4 MD, Etan Marks4 MD, Daniel Rivlin3 MD Affiliations: 1Department of Dermatology, LECOM- Larkin Community Hospital, Miami, Florida, USA, 2Department of Dermatology, KCUMB - Advanced Dermatology and Cosmetic Surgery, Orlando, Florida, USA, 3Department of Dermatology, LECOM- Skin and Cancer Associates, Miami Beach, Florida, USA, 4Department of Dermatopathology Advanced Dermatology and Cosmetic Surgery Pathology Laboratory, Delray Beach, Florida, USA Corresponding Author: Jennifer Seyffert DO, 4308 Alton Road, Suite 510, Miami Beach, FL 33140, Tel: 305-674-8865, Fax: 305-674-1459, Email: jseyf12@gmail.com Abstract: Perivascular epithelioid cell tumors, also known as PEComas, are mesenchymal neoplasms which uncommonly originate within the skin, with only 23 cases documented within the literature. These rare neoplasms classically display epithelioid cells composed of granular or clear cytoplasm arranged in sheets, nests, or cords. Their immunoreactivity for melanocytic and smooth muscle markers makes these tumors distinct and unique.[1] We herein present two cases of primary cutaneous PEComas that clinically mimic other common cutaneous neoplasms and illustrate the necessity for clinical-pathologic correlation. A literature review is also presented to compare the different clinical and histological presentations of cutaneous PEComas.

An adult male free-living yellow armadillo (Euphractus sexcinctus) was found by hunters and referred for clinical evaluation because of a tumour-like lesion on the carapace. The animal was lethargic and weak with severe dehydration, enophthalmos and cachexia, and was euthanized because of its very poor clinical condition. Necropsy revealed a whitish, exophytic, irregular and moist mass (7 × 6.5 × 1.5 cm) in the caudal third of the carapace. On cut section, the mass was hard, compact, irregular and whitish. Histopathology revealed a densely cellular, expansive, poorly delimited neoplasm composed of malignant mesenchymal cells arranged in islands and cords, interspersed by numerous areas of irregularly mineralized osteoid matrix. Neoplastic cells were intensely immunolabelled for vimentin. The diagnosis of a high-grade osteosarcoma of osteoblastic subtype was based on the clinical, gross, histopathological and immunohistochemical findings. This first report of an osteosarcoma in an armadillo expands the list of armadillo diseases and will assist the management of these animals by veterinarians. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Intramuscular myxoma (IMM) is a benign soft tissue tumor of mesenchymal origin that occurs mainly in skeletal muscles which can be removed through surgery after diagnosis. Intramuscular myxoma (IMM) is a benign soft tissue tumor of mesenchymal origin that typically occurs in skeletal muscles. Its diagnosis is based on magnetic resonance imaging (MRI) and histopathologic evaluation of the lesion. In our report, we describe the case of a 60‐year‐old female with an IMM in the supinator muscle of the right forearm, which was confirmed by MRI and histopathologic examination. Following surgery to remove the mass, a follow‐up confirmed the patient's recovery and the absence of movement limitations in the elbow joint. [ABSTRACT FROM AUTHOR]

Mazabraud's syndrome represents rare benign disorder characterized by simultaneous occurrence of fibrous dysplasia of bone and intramuscular myxomas within surrounding soft tissue. Mutations of GNAS1 gene were proven to be causative for this condition. Here, we present a case report of a patient with unusual manifestation of this disease, who developed a pathological fracture of the femur in the setting of monostotic fibrous dysplasia. The intramuscular myxoma of the thigh was discovered during the following orthopedic operation, where the intraoperative diagnosis became a pitfall of the case, as the intramuscular myxoma was initially diagnosed as a low-grade sarcoma from the frozen section. Apart from clinical findings, the diagnosis of Mazabraud's syndrome was further proven by histopathological evaluation and molecular studies of GNAS1 gene. This case raises awareness of such condition as it can easily become a diagnostic pitfall.

Aggressive Angiomyxoma is most commonly identified as a slow growing mesenchymal neoplasm most commonly seen in women than in men. It has a marked tendency for local recurrence but with low instances of metastasis. Radiological investigations may assist in arriving at a provisional diagnosis and provide an arbitrary idea about the margins of the tumour but the gold standard diagnosis is always be histopathological examination. Surgery is the first line and the most reliable form of treatment. However, around 40-70% of patients came with complaints of recurrence. This is a case of a 61-year-old male patient who came with complaints of scrotal swelling which increased in size over a period of six months. The swelling was firm in consistency without warmth or tenderness. Contrast-enhanced Magnetic Resonance Imaging (CE-MRI) was taken to discern the borders of the mass and it was suspected to be a soft tissue sarcoma. Mass was excised in toto and a confirmatory diagnosis of aggressive angiomyxoma was made only after postoperative histopathological examination. The patient was on regular follow-up for 8 months to date and no evidence of local recurrence was detected. This case report presents to be a curious case as aggressive angiomyxomas are usually tumours seen in females. It also describes the management of scrotal swelling without a preoperative diagnosis.

With the expanding possibilities of human genome research in recent years, the number of cases of soft tissue tumors that we are able to classify into the correct subgroups and to reveal their molecular profile is increasing. Among such tumors, we can also consider neoplasms that have a specific fusion of genes, in our case namely the pleomorphic adenoma gene 1 (PLAG1) and its partner. PLAG1 gene fusions were previously associated mainly with salivary gland pleomorphic adenomas, lipoblastomas, myoepithelial tumors, uterine epitheloid, myxoid leiomyosarcomas, and, recently, with PLAG1-rearranged fibromyxoid soft tissue tumors. To our knowledge, we report the first case of a soft tissue tumor with a PLAG1 fusion gene in an adult. In our case, we detected a new H3-3B::PLAG1 fusion in a soft tissue tumor, which originally appeared as nodular fasciitis., (© 2024 The Author(s). Genes, Chromosomes and Cancer published by Wiley Periodicals LLC.)

Background: CD34 is a transmembrane phosphoglycoprotein that plays a role in modulating cell adhesion and myofibroblastic differentiation. A superficial CD34-positive fibroblastic tumor was first identified as a clinical and pathological entity in 2014; it is a rare mesenchymal neoplasm of borderline malignancy that can occur in the superficial adipose tissue anywhere on the body. Case Report: This is a case of a female patient aged 38 years who was referred to a surgeon due to tumefaction in the left paraxial region. The tumor was excised in toto and pathohistological analysis confirmed a superficial CD34-positive fibroblastic tumor. Immunohistochemical staining was positive for CD34 and additional analysis for signal transducer and activator of transcription and mouse double minute 2 proteins revealed negative staining. It was decided that no additional therapy was needed; however, regular follow-ups were recommended. Conclusion: This case posed an additional diagnostic and therapeutic challenge due to the localization of the tumor in the breast of a female patient. Special care was needed to exclude a possible breast neoplasm as well as dermal or soft tissue neoplasm. Diagnosis of a superficial CD34-positive fibroblastic tumor should be considered in all CD34-positive tumors with bizarre, irregular nuclei and no proliferative activity. [ABSTRACT FROM AUTHOR]

Synovial Sarcoma (SS) is a rare mesenchymal neoplasm arising commonly from the periarticular tissue. Primary SS involving the lung accounts for less than 0.5% of all lung tumours. SS are high grade aggressive tumours affecting the extremities of adolescents and young adults. Clinically, patient presents with cough, breathing difficulty, chest pain or haemoptysis and imaging studies may reveal a mass lesion but for definitive diagnosis, histopathology and immunohistochemical examination is needed. Hereby, authors report a case of 39-year-old female diagnosed with primary pulmonary SS with particular emphasis on the pathologic findings.

Myxoma is a rare benign mesenchymal neoplasm. Scrotal myxomas can be either cutaneous or intramuscular. Muscular myxomas are usually found in cardiac muscles and skeletal muscles of the extremities. The most common locations of cutaneous myxomas are the trunk, lower extremities, and the head and neck. However, these lesions can rarely arise in the genital area (vulva, mons pubis, and scrotum). The clinical presentation of this lesion is nonspecific, and it is difficult to make a diagnosis before a biopsy and microscopic examination. Scrotal myxomas are infrequent and can cause definite diagnostic problems.  We report a case of a 64-year-old male who presented to the surgery outpatient department with a history of scrotal swelling for 20 years. The swelling was excised and sent for histopathological examination. Histopathological examination revealed features of scrotal cutaneous myxoma., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Devi D et al.)

Mammary-type myofibroblastoma is a rare benign neoplasm of mesenchymal origin. Presentation outside of the embryological mammary crest is exceedingly rare. This case report documents the presentation of a 40 year old male who presented with a painless infra-auricular swelling. We discuss histological, clinical and radiological findings as well as the challenges of managing spindle cell lesions within the head and neck region.

Primary solitary fibrous tumor (SFT) of the thyroid gland is a rare mesenchymal tumor with fibroblastic differentiation, ramified, thin-walled, enlarged (staghorn) vessels and specific NAB2-STAT6 gene fusion, which is more commonly found in pleura and peritoneum. This neoplasm can be located in a variety of anatomical sites outside pleura and peritoneum including bone, visceral organs and soft tissues, head and neck examples representing only 10-15% of the extra-pleural and extra-peritoneal tumors. Diagnosing this entity can be difficult, especially in thyroid gland, mainly because of the rarity of this neoplasm, but presence of characteristic microscopic features together with positivity for STAT6 and CD34 can confirm the diagnosis and exclude other differential diagnosis. Information about the diagnosis and treatment options of thyroid SFTs is limited but almost all primary thyroid SFTs have a good prognosis and indolent clinical course. Clinical surveillance is still necessary because some SFTs can be aggressive. Raising awareness regarding extra-pleural and extraperitoneal location of this tumor in endocrine organs can help to better manage these patients. We report the case of a 34-year-old female with primary SFT of the thyroid gland. Additionally, we review the literature for the main clinical, paraclinical and pathological features of this neoplasm. [ABSTRACT FROM AUTHOR]

Introduction: Uterine tumors resembling ovarian sex cord tumor (UTROSCT) are a unique group of neoplasms with diverse morphology and immunophenotypic characteristics, coexpressing sex cord, epithelial, and smooth-muscle markers. To date, less than 100 cases have been reported and there is paucity of data concerning their clinical behavior. Materials and Methods: All cases of uterine body tumors diagnosed over a period of two and a half years (2016-2018) were retrieved. Histopathological features were reviewed and extended panel of immunohistochemistry was performed to identify cases of UTROSCTs. Results: Six cases of UTROSCTs were identified with a median age of 46.5 years. Four of them presented with menorrhagia, while two with postmenopausal bleeding including one with a history of carcinoma breast. Three of these cases were initially misdiagnosed as endometrial stromal sarcoma and adenocarcinomas. They all underwent hysterectomy with bilateral salpingo-oophorectomy. Conclusion: It is considered a tumor with low malignant potential; however, one out of six cases (16.7%) in our study showed metastasis, within 1 year of diagnosis. It is important to recognize this entity as it mimics a wide range of both benign and malignant tumors. Molecular pathogenesis and exact management protocols remain elusive due to rarity,hence, multi-institutional studies are warranted.

Extra-mammary myofibroblastomas are rare benign mesenchymal neoplasms, histologically and immune-phenotypically identical to mammary myofibroblastomas. Histologically, they are characterized by the abundance of spindle cells in hyalinized collagenous stroma with positive expression of CD 34 and desmin. We present an extremely rare case of extra-mammary myofibroblastoma of the orbit in a 29-year – old male who presented with painless proptosis of the right eye, with a description of clinical, radiological, and histological findings. [ABSTRACT FROM AUTHOR]

Solitary fibrous tumour (SFT) is a rare mesenchymal tumour, usually originating from the serous surfaces, typically of the pleura and pericardium. However, it can also have localizations in soft tissues and visceral organs. We report the case of a 79-year-old woman affected by mesenteric SFT, localized in the sigmoid colon. We performed open excision of the abovementioned mass en-bloc with the sigmoid colon and left adnexal tissues. Pathological examination of surgical specimen revealed a diagnosis of SFT CD34+, high-risk of metastases. Mesenteric SFTs are even rarer forms of SFT and may be asymptomatic or cause intestinal occlusion. There is no consensus on the management of this tumour. Radical surgical excision is the only curative treatment, while adjuvant therapies are indicated in case of advanced disease. Due to the high metastatic risk of malignant forms, a long follow-up is mandatory in these cases. [ABSTRACT FROM AUTHOR]

Background: Extraskeletal osteosarcoma (EOS), a rare variant of osteosarcoma (OS), is a malignant neoplasm that develops in soft tissues without primary bone involvement. This study aims to describe a case of EOS with a mediastinal location in a canine. Case: A 10-year-old male Uruguayan Cimarron dog, was presented to the Laboratório Regional de Diagnóstico, Faculdade de Veterinária, Universidade Federal de Pelotas (LRD/FV/UFPel) for necropsy. The dog had a history of submandibular swelling, progressive hind limb paralysis, muscle atrophy, and breathing difficulties. During necropsy, in the thoracic cavity, approximately 900 mL of serosanguinous exudate and a reddish-brown, bossed mediastinal mass measuring 15.0 cm in the longest axis were also noted. The lung exhibited multifocal to coalescent, white, firm nodules extending from the pleura to the parenchyma and measuring up to 4.5 cm in diameter. In the parietal and occipital region of the brain, a matte wine mass measuring 2.3 cm in the longest axis was observed. Fragments of the neoplastic mass, organs of the abdominal and thoracic cavities, and the brain were harvested and fixed in 10% buffered formalin. After 48 h, the samples were routinely processed, incorporated in paraffin, cut into 3 µm-thick sections, and stained using Hematoxylin and Eosin (HE). Selected sections of the neoplasm, the lung, and the brain were subjected to Von Kossa staining and immunohistochemical (IHC) analysis. For IHC, primary anti-cytokeratin monoclonal antibodies (clone AE1 / AE3, BioCare Medical) at a 1:100 dilution, vimentin (clone V9, BioCare Medical) at a 1:100 dilution, S100 Protein (clone 15E2E2, BioCare Medical) at a 1:100 dilution, and Ki67 (SP6 clone, BioCare Medical) at a 1:50 dilution were used. Immunostaining was visualized using 3-3' diaminabenzidine (DAB). Histological evaluation of the mediastinal mass, the pulmonary nodules, and the central nervous system among polygonal mesenchymal cells was conducted. Marked pleomorphism with euchromatic, rounded to oval nuclei, evident nucleoli, and poorly delimited eosinophilic cytoplasm. Neoplastic cells were arranged in nests and bundles with an invasive growth pattern. Osteoid and bone matrix formation as well as multinucleated giant cells of the osteoclast type were observed. The bone matrix was better evidenced in Von Kossa staining. IHC in all analyzed sections of the neoplastic cells showed positive immunostaining for Vimentin and Ki67. In the sections incubated with anti-cytokeratin and S100 protein antibodies showed no presence of neoplastic cells. Discussion: The diagnosis of EOS was based on the absence of primary bone lesions during microscopic necroscopy and on the exclusion of other histogenetic origins using IHC. The absence of primary bone lesions was the main attribute that differentiates EOS from other variants osteosarcomas, such as central/medullary and surface OS (periosteal and paraosteal) most frequently in canine species. The origin of EOS is uncertain. However, its occurrence has been originated with in pluripotent cells or previous injuries, such as retention of surgical sponges and vaccination sites. In this case, since the animal had no clinical history of injuries or surgical procedures that could induce the formation of a mediastinal neoplasm, the probable origin of the neoplasm was pluripotent cells. In dogs, EOS occurs mainly in the mammary glands, digestive system, liver, spleen, and subcutaneous tissue. Furthermore, the mediastinal location observed in this study was described only in goats. The clinical signs are nonspecific and varies with the location of the tumor, as observed in the present report. EOS may also present mediastinal location in the canine species. Necropsy, histopathological examination, and IHC were essential to establish the diagnosis of this OS variant. [ABSTRACT FROM AUTHOR]

Primary thyroid angiosarcoma is a very rare and extremely aggressive mesenchymal malignant neoplasm showing morphological and immunophenotypic evidence of endothelial cell differentiation. Early diagnosis of this tumor along with radical thyroidectomy followed by postoperative radiotherapy and chemotherapy are essential for adequate management of the patient. Currently available data on diagnosis and treatment options of this neoplasm are limited because it is a rare disease in endocrine organs. Raising awareness regarding its diagnosis can help to optimize the treatment and to improve the survival of the patient. We present the case of a 72-year-old female patient with multiple comorbidities who addressed to the hospital with obstructive respiratory symptoms: dyspnea, wheezing and hoarseness. The investigations, both clinical and paraclinical, identified a local invasive cervical mass located mainly in the left thyroid lobe, whose immunohistochemical examination confirmed primary thyroid angiosarcoma. Although this type of neoplasm is described mainly in the Alpine regions, it can appear in lower altitude regions and this tumor needs to be differentiated from a highgrade neoplasm (anaplastic thyroid carcinoma). [ABSTRACT FROM AUTHOR]

Fibrous histiocytoma is a mesenchymal neoplasm with benign and malignant varieties. This tumor mainly affects the skin of extremities in adults and may on rare occasions affect the oral cavity. The tumor has radiographic features in very rare cases. The present case report aims to conduct a clinicopathological-radiographic and immunohistochemical assessment and treatment of a patient with this lesion. [ABSTRACT FROM AUTHOR]

Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms constituting less than 2% of all soft tissue tumors. They typically originate in the thoracic cavity, mainly in the pleura, but can also occur in other various sites such as lung parenchyma, pericardium, and bronchus. In this study, a 49-year-old non-smoking female with a history of allergies presented to our pulmonary clinic with a chronic cough. An explorative bronchoscopy revealed an intrabronchial mass in the left superior bronchi, and a 68 Ga-DOTATOC positron emission computed tomography suggested a carcinoid tumor. Subsequent pulmonary segmentectomy unveiled a well-circumscribed polypoid lesion diagnosed as a low-grade bronchus SFT through histopathological and immunohistochemical assessments. The patient was asymptomatic after surgical excision and showed no other lesion during the 6-month follow-up. The endobronchial location of SFT is uncommon, with only a few reported cases in the literature, underscoring the necessity of considering various differential diagnoses, including carcinoid, mucoepidermoid carcinoma, endobronchial pleomorphic adenoma, hamartoma, leiomyoma, and metastasis, depending on location and imaging features. This report underscores the importance of careful histological and immunohistochemical evaluation in understanding and appropriately stratifying the risk associated with polypoid lesions. [ABSTRACT FROM AUTHOR]

Abstract Background Solitary fibrous tumor is an uncommon soft tissue neoplasm with intermediate biological behavior, which rarely metastasizes. Malignant solitary fibrous tumor, although not clearly defined, is rarely described in the prostate. The present case is characterized by some peculiarities if compared with previously reported cases of prostatic malignant solitary fibrous tumor. Firstly, it does not show a homogeneous morphology: part of the neoplasm (about 50%) showed the features of a conventional solitary fibrous tumor, while the remaining part showed the features of a malignant solitary fibrous tumor. In addition, the case is the first malignant solitary fibrous tumor reaching a huge diameter of 20 cm and replacing all prostatic parenchyma. Interestingly, normal prostatic parenchyma was observed on left-lobe trans-rectal needle-core biopsies, but was totally absent in surgical specimen. Since radical prostatectomy was carried out about 4 months after the biopsies, such discordant data may suggest exceedingly rapid growth of the neoplasm. Case presentation We report a case of a 62-year-old male, presented at medical observation for urinary retention, constipation and an enlarged prostate gland. A trans-rectal prostatic biopsy showed a low-grade spindle cell neoplasm. Histopathological examination of the prostatectomy specimen showed patternless architecture with hypocellular and hypercellular areas and hemangiopericytoma-like vessels. In some fields the neoplasm was characterized by a high mitotic index and evident cellular atypia. Immunohistochemically, neoplastic cells were positive for CD34, bcl2, CD99, STAT6 and partially for PgR. The neoplasm was diagnosed as a malignant solitary fibrous tumor. Conclusions The differential diagnosis of spindle cells tumors arising in the prostrate is broad and includes lesions of epithelial and mesenchymal origin, primary prostatic lesions such as stromal tumors of uncertain malignant potential and stromal sarcoma, as well as anatomically ubiquitous soft tissue neoplasms. Solitary fibrous tumors should be considered in cases of prostatic tumors with a spindled morphology, but malignancy in such tumors is extremely rare in the prostate. A review of literature showed only four additional cases. Because of the unpredictable biological behavior and the possibility of recurrence, a long-term clinical and instrumental follow-up is recommended.

A malignant gastrointestinal neuroectodermal tumor (GNET) is a rare entity, characterized as a malignant mesenchymal neoplasm occurring exclusively near the gastrointestinal tract, prone to frequent local recurrence and metastasis. Here, we report a case of a 49-year-old male presented with abdominal pain and weight loss. The patient had a remote history of thymic B-cell lymphoma. An abdominal computed tomography (CT) scan revealed a focal wall thickening of the terminal ileum with mesenteric lymphadenopathy, suggestive of lymphoma. A core needle biopsy of the mesenteric node was inconclusive. A right hemicolectomy was subsequently performed. Histologically, abundant multinucleated osteoclast-like giant cells are present. The tumor cells show diffuse strong positivity for S100 and SOX10. EWSR1-ATF1 gene fusion was identified by fluorescence in situ hybridization (FISH), consistent with a diagnosis of GNET. This case emphasizes a diagnostic challenge of a rare malignancy., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Jia et al.)

Calcifying fibrous tumor (CFT) is a rare benign lesion of mesenchymal origin that may present similar characteristics to other more common tumors. We present the case of a 36-year-old woman with a tumor in the proximal jejunum, initially suspected to be a gastrointestinal stromal tumor (GIST). Surgical resection was performed, revealing a well-demarcated nodule at the anti-mesenteric border with microscopic features typical of a calcifying fibrous tumor. The tumor cells were positive for CD34 and negative for other markers, differentiating it from other neoplasms. Calcifying fibrous tumors can be confused with more common tumors because of its appearance, but an accurate diagnosis supported by immunohistochemistry is essential. Complete surgical excision is usually curative., (Copyright © 2023 Sociedad Española de Anatomía Patológica. Publicado por Elsevier España, S.L.U. All rights reserved.)

Solitary fibrous tumor (SFT) of the lung is a rare mesenchymal neoplasm of uncertain histogenesis, unknown molecular features, and unpredictable clinical behavior, characterized by NAB2-STAT6 fusion. Hypoglycemia accompanying SFT (Doege-Potter syndrome) is an uncommon presentation. We present the cytomorphological features on biopsy imprint smears of a histopathologically confirmed case of SFT of the lung with an uncommon presentation. A 76-year-old non-smoker, non-alcoholic, and non-diabetic man presented with complaints of intermittent episodes of confusion with syncopal attacks (>10 episodes) for six months. The patient had no respiratory complaints and no history of weight loss. Laboratory investigations revealed fasting blood sugar of 38 mg/dl with low serum insulin and C-peptide levels. Physical examination revealed reduced air entry on the left side of the chest. Chest X-ray showed left-sided homogenous opacity. High-resolution computed tomography (HRCT) of the chest showed a large left-sided lung mass. A biopsy was performed. Biopsy imprint smears were cellular and showed tumor cells arranged in clusters and fragments with traversing capillaries displaying monomorphic pump to oval nuclei, fine granular evenly dispersed chromatin, regular nuclear membrane, inconspicuous nucleoli, and a moderate amount of wispy cytoplasm. Foci of intercellular hyaline stromal material were noted. A cytodiagnosis of low-grade mesenchymal neoplasm was made. Histopathology revealed a cellular tumor comprising tightly packed round to fusiform cells arranged around blood vessels with intervening thick collagen, positive for CD99, vimentin, BCL2, CD34, and STAT6 and negative for EMA, CK AE1/AE3, S100, TLE1, and SMA. Familiarity with cytomorphology plays a pivotal role in clinching an early diagnosis of this rare neoplasm of the lung, particularly in the setting of presentation with hypoglycemia., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Pulikkal et al.)

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal lesions of the gastrointestinal tract. A small minority of GISTs exhibit morphologic and phenotypic changes and differentiate into an unusual phenotype through the process of dedifferentiation. Dedifferentiation can occur either de novo or after prolonged treatment with imatinib, a selective tyrosine kinase inhibitor. GISTs can present with various morphologies including rhabdomyosarcoma, angiosarcoma, or undifferentiated pleomorphic sarcoma. The unusual histologic and immunohistochemical characteristics of these tumors can be diagnostically challenging. Therefore, it is essential that the pathologists recognize GISTs with unusual morphology and be aware of the dedifferentiation process. This review aims to provide an overview of the morphologic and molecular features of dedifferentiated GISTs. Additionally, we discuss diagnostic dilemmas and recent immunohistochemical markers that are useful in distinguishing dedifferentiated GISTs from other gastrointestinal tumors. • We highlight the molecular alterations underlying GIST dedifferentiation. • We discuss critical morphologic and molecular markers supporting dedifferentiated GIST diagnosis. • Protein kinase C theta (PKC θ) and carbonic anhydrase II (CAII) are new, useful biomarkers in GIST diagnosis. • We discuss pitfalls and diagnostic challenges that pathologists can encounter in routine practice. [ABSTRACT FROM AUTHOR]

Endometrial stromal sarcomas are rare malignant mesenchymal tumors, occurring in the age group of 45–55 years. We report a case of low-grade endometrial stromal sarcoma in a 39-year-old woman, whose ultrasound examination suggested a large endometrial polyp. Polypectomy followed by laparoscopic total hysterectomy with bilateral salpingo-oophorectomy was performed. The final histological examination showed no residual disease, implying that the tumor was totally resected during hysteroscopy. This case report highlights that endometrial stromal sarcoma is to be included in the differential diagnosis of endometrial polyp though rare. [ABSTRACT FROM AUTHOR]

Solitary fibrous tumor is a mesenchymal neoplasm that first appeared in the literature as a pleural lesion, but over the last decades, it has been reported in many extrathoracic sites. Primary solitary fibrous tumor in the adrenal gland is very uncommon. Its biological behavior is variable but mostly benign. We report here a case of an apparently healthy woman who, in the context of the study of limb paresthesias, was diagnosed with an adrenal incidentaloma. Laboratory tests were performed, and no hormone hyperfunction was detected. Subsequently, a right adrenalectomy was performed, and the pathological study confirmed a solitary fibrous tumor. To the best of our knowledge, this is the 19th case reported in the literature of a primary solitary fibrous tumor originating from the adrenal gland and, notably, the first documented instance in Spain., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Casademunt-Gras et al.)

Angiomyxolipoma is considered a very rare subtype of lipoma, with the latter being the most common type of mesenchymal neoplasm. Only 17 cases have been described in English medical literature. Angiomyxolipomas have been described in many locations, mostly in the subcutaneous tissue. In this report, we present the first case of renal angiomyxolipoma ever encountered. Diagnosis was made after many differential diagnoses had been ruled out. Subsequent management and follow-up are illustrated along with a discussion and review of literature.

Epithelioid sarcoma is a rare malignant mesenchymal neoplasm (less than 1% of all sarcomas) with epithelioid morphology. Among the 2 subtypes, proximal represents only one-third of cases and commonly involves deep tissues of pelvic region, including the perineum, genital area, and groin, and occurs more frequently in older patients who present a more aggressive course. In the female genital tract, proximal-type epithelioid sarcoma (PES) mainly affects the vulva and is extremely uncommon in the uterus. To our knowledge, only a few cases of PES involving the cervix and uterine body have been previously reported in the literature. We report a 23-year-old woman who presented with abnormal vaginal bleeding. She was found to have a cervical mass, which was resected and diagnosed as a hemangioendothelioma. However, 2 months later, the mass recurred and the histopathological analysis at our institution demonstrated a PES confined to the uterine cervix. It is important to include this neoplasm in the differential diagnosis of epithelioid tumors that can involve the female genital tract because it has a significant impact on prognosis and treatment. [ABSTRACT FROM AUTHOR]

Background: Solitary fibrous tumor is an uncommon soft tissue neoplasm with intermediate biological behavior, which rarely metastasizes. Malignant solitary fibrous tumor, although not clearly defined, is rarely described in the prostate. The present case is characterized by some peculiarities if compared with previously reported cases of prostatic malignant solitary fibrous tumor. Firstly, it does not show a homogeneous morphology: part of the neoplasm (about 50%) showed the features of a conventional solitary fibrous tumor, while the remaining part showed the features of a malignant solitary fibrous tumor. In addition, the case is the first malignant solitary fibrous tumor reaching a huge diameter of 20 cm and replacing all prostatic parenchyma. Interestingly, normal prostatic parenchyma was observed on left-lobe trans-rectal needle-core biopsies, but was totally absent in surgical specimen. Since radical prostatectomy was carried out about 4 months after the biopsies, such discordant data may suggest exceedingly rapid growth of the neoplasm. Case presentation: We report a case of a 62-year-old male, presented at medical observation for urinary retention, constipation and an enlarged prostate gland. A trans-rectal prostatic biopsy showed a low-grade spindle cell neoplasm. Histopathological examination of the prostatectomy specimen showed patternless architecture with hypocellular and hypercellular areas and hemangiopericytoma-like vessels. In some fields the neoplasm was characterized by a high mitotic index and evident cellular atypia. Immunohistochemically, neoplastic cells were positive for CD34, bcl2, CD99, STAT6 and partially for PgR. The neoplasm was diagnosed as a malignant solitary fibrous tumor. Conclusions: The differential diagnosis of spindle cells tumors arising in the prostrate is broad and includes lesions of epithelial and mesenchymal origin, primary prostatic lesions such as stromal tumors of uncertain malignant potential and stromal sarcoma, as well as anatomically ubiquitous soft tissue neoplasms. Solitary fibrous tumors should be considered in cases of prostatic tumors with a spindled morphology, but malignancy in such tumors is extremely rare in the prostate. A review of literature showed only four additional cases. Because of the unpredictable biological behavior and the possibility of recurrence, a long-term clinical and instrumental follow-up is recommended. [ABSTRACT FROM AUTHOR]

Gastrointestinal stromal tumors (GISTs) are rare lesions of the gastrointestinal tract that have a strong predisposition to the stomach and small intestine. We present a case of an 89-year-old female who initially presented to the emergency room with signs and symptoms of acute decompensated heart failure (HF) and was later discovered to have a 23-centimeter GIST in her abdominal cavity. This case emphasizes the implications of large intraperitoneal neoplasms and the unique constellation of symptoms they may present with., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Marsalisi et al.)

Adenocarcinoma is the most common histological type of gastric tumour, accounting for approximately 95% of all gastric carcinomas. Gastrointestinal stromal tumours (GISTs) are rare mesenchymal neoplasms of the digestive tract. Synchronous adenocarcinoma and gastrointestinal stromal tumour (GIST) occurring in the stomach is rare and very few cases have been reported in literature. Synchronous tumours in the stomach are rarely diagnosed preoperatively. A 63-year-old gentleman was diagnosed with a gastric adenocarcinoma on endoscopic biopsy and underwent surgery. Postoperative histopathologic examination revealed 2 synchronous tumours with both adenocarcinoma and GIST. The adenocarcinoma was determined to be the aggressive tumour based on histologic features. GIST was categorized as a very low risk of malignancy, based on its size and mitosis. The patient underwent chemotherapy for adenocarcinoma. He is under follow up and is currently disease free. Careful histopathologic evaluation is required to detect co-existing rare synchronous tumours. Presence of the second tumour may require additional procedures or protocols.