Malignant Epithelioid Soft Tissue Tumours- A Pathologist's Perspective With Review of Literature

Neck Epithelioid Sarcoma at an Unusual Location Mimicking Lymph Node Metastases of Nasopharyngeal Carcinoma: A Case Report

Epithelioid sarcoma (ES) is an uncommon soft tissue sarcoma. It is usually located in the extremities and exceptionally in the neck. Its diagnosis constitutes a real challenge which is based on histology and immunohistochemistry staining that must be interpreted with caution given the anatomopathological similarities to other tumors. In this article, we report a case of a 37-year-old man admitted for a locally advanced ES of the neck. There were suspicions of lymph node metastases of nasopharyngeal carcinoma at the first pathological examination. The patient received palliative chemotherapy and was referred to the supportive care department. Through this case, we will discuss the clinical and anatomopathological characteristics and therapeutic options of this extremely rare tumor which poses a diagnostic challenge.

Malignant Perivascular Epithelioid Cell Neoplasm of Left Kidney Treated With Targeted Therapy: A Rare Case Report

Perivascular epithelioid cell neoplasm (PEComa) is one of the rare entities which is challenging to diagnose clinically. These tumors occur due to tuberous sclerosis complex gene mutations leading to upregulation and overexpression of the mammalian target of rapamycin (mTOR). Malignant PEComas are rare, and we report a peculiar case of PEComa treated with mTOR inhibitors. A 43-year-old woman presented with complaints of back pain, intermittent fever, dysuria, and cough with expectoration for one month. Abdominal computed tomography (CT) revealed heterogeneously enhancing exophytic mass of the left kidney. A positron emission tomography CT whole body showed a primary malignancy in the left kidney, sclerotic lesions in the bony skeleton, and lymphangitis carcinomatosis in both lungs. A biopsy of the left renal mass revealed PEComa, focally positive for melanocytic and muscle markers. She was commenced on treatment with intravenous temsirolimus, and there was a complete tumor regression by the end of the completion of six cycles.

Primary Epithelioid Angiosarcoma of the Colon With Peritoneal Carcinomatosis

Angiosarcoma is a rare mesenchymal tissue neoplasm, typically involving lymphatic or vascular endothelial cells. The tumor can arise anywhere in the body, though it is most often found as cutaneous lesions in the head and neck region. Due to its rarity, a diagnosis can sometimes be missed, especially when the sarcoma involves an uncommon site like the gastrointestinal tract. In this case, we describe a male patient who was found to have primary epithelioid angiosarcoma of the colon. Initial biopsies with immunohistochemistry staining were weakly positive for anti-cytokeratin (CAM 5.2) and negative for SRY-Box transcription factor 10 (SOX-10) and B-cell-specific activator protein (PAX-5). He was misdiagnosed as having poorly differentiated carcinoma as a result. However, a more in-depth look at the colon specimen after tumor resection revealed CD-31 and factor VIII positivity, which established the diagnosis of epithelioid angiosarcoma of the colon. This case suggests the use of rare histopathology markers as part of the workup for colonic lesions to confirm the diagnosis, especially when tissue biopsy is limited.

Practical Approach to Histological Diagnosis of Peripheral Nerve Sheath Tumors: An Update

Peripheral nerve sheath tumors encompass a wide spectrum of lesions with different biological behavior, including both benign and malignant neoplasms as well as the recent diagnostic category, i.e., “atypical neurofibromatous neoplasm with uncertain biologic potential” to be used only for NF1 patients. Neurofibromas and schwannomas are benign Schwann-cell-derived peripheral nerve sheath tumors arising as isolated lesions or within the context of classical neurofibromatosis or schwannomatoses. Multiple tumors are a hallmark of neurofibromatosis type 1(NF1) and related forms, NF2-related-schwannomatosis (formerly NF2) or SMARCB1/LZTR1-related schwannomatoses. Perineuriomas are benign, mostly sporadic, peripheral nerve sheath tumors that show morphological, immunohistochemical, and ultrastructural features reminiscent of perineurial differentiation. Hybrid tumors exist, with the most common lesions represented by a variable mixture of neurofibromas, schwannomas, and perineuriomas. Conversely, malignant peripheral nerve sheath tumors are soft tissue sarcomas that may arise from a peripheral nerve or a pre-existing neurofibroma, and in about 50% of cases, these tumors are associated with NF1. The present review emphasizes the main clinicopathologic features of each pathological entity, focusing on the diagnostic clues and unusual morphological variants.

Epithelioid Haemangioma of Bone: A Case Series and Comprehensive Literature Review Reappraising the Diagnostic Classification of All Epithelioid Vascular Neoplasms of Bone

Epithelioid vascular neoplasms of the bone are classified by the World Health Organization (WHO) into only two tiers: low-grade epithelioid hemangioma (EH) and a more malignant category including both epithelioid hemangioendothelioma and epithelioid angiosarcoma. The World Health Organization defines bone EH as a locally aggressive neoplasm with no connotation of benign or intermediate malignancy. We reviewed three cases of EH in our lab archives with the perspective of appraising their histomorphological approach toward diagnosis. Patients were in the age range of 15-25 years. The site of the neoplasms ranged from the carpal bones to the metatarsal bones. Histomorphological examination of the lesions showed a nodular growth pattern of a vascular neoplasm without demonstrable vessel origin. The vasoformative area increased from the center to the periphery, with prominent epithelioid morphology of the endothelial cells at the periphery and an associated inflammatory infiltrate comprising eosinophils, lymphocytes, and plasma cells. The growth pattern was diffuse, with extension into the deeper dermis of overlying skin.