Diagnosing liposarcoma on (peri)-renal mass biopsy: A clinicopathological study of 30 cases.

AIMS: Classification of renal neoplasms on small tissue biopsies is in increasing demand, and maintaining broad differential diagnostic considerations in this setting is necessary. When evaluating a renal or perirenal tumour biopsy with sarcomatoid morphology, together with sarcomatoid renal cell carcinoma and sarcomatoid urothelial carcinoma as top diagnostic considerations, it is vital to additionally consider the possibility of well-differentiated and de-differentiated liposarcoma. METHODS AND RESULTS: This study reports a series of 30 biopsy samples from sites in or around the kidney collected from four institutions in which the correct diagnosis was either well-differentiated or de-differentiated liposarcoma. The majority (26 of 30, 87%) of lesions were accurately diagnosed on biopsy sampling, all of which incorporated testing for MDM2 by immunohistochemistry (IHC), fluorescence in-situ hybridisation (FISH) or a combination of the two as part of the diagnostic work-up. Tumour expression of MDM2 by IHC without confirmatory FISH analysis was sometimes (30%) sufficient to reach a diagnosis, but demonstration of MDM2 amplification by FISH was ascertained in the majority (57%) of biopsy samples. A diagnosis of de-differentiated liposarcoma was not definitively established until resection in four (13%) patients, as no MDM2 testing was performed on the corresponding pre-operative biopsies. CONCLUSIONS: When a retroperitoneal tumour is not clinically suspected, histological consideration of a liposarcoma diagnosis may be overlooked. Implementation of ancillary immunohistochemical and cytogenetic testing can ultimately lead to a definitive diagnosis in this potentially misleading anatomical location.

Superficial dedifferentiated liposarcoma: A clinicopathologic study.

INTRODUCTION: Dedifferentiation occurs in approximately 10% of atypical lipomatous tumors/well-differentiated liposarcomas (ALT/WDLPS), primarily in retroperitoneal or deep-seated tumors, conferring metastatic potential. Superficial dedifferentiated liposarcoma (sDDLPS) is rare, and its progression and natural history are poorly documented. METHODS: We performed a 15-year retrospective review of our pathology database to identify cases of DDLPS in the skin or subcutaneous tissue. Diagnosis of primary sDDLPS required evidence of non-lipogenic sarcoma in the skin or subcutis, with concurrent ALT/WDLPS and/or MDM2 amplification. RESULTS: We identified 14 cases of DDLPS involving skin or subcutis: 7 primary sDDLPS and 7 secondary lesions (3 from recurrent deep DDLPS and 4 from metastasis). Primary sDDLPS cases (4 females, 3 males; median age: 74) mainly presented as undifferentiated spindle cell or pleomorphic sarcoma. Tumor grades were grade 2 (5 cases) and grade 3 (2 cases), with three cases also showing grade 1 areas. MDM2 amplification was confirmed in 6 sDDLPSs for which FISH was successfully performed. Follow-up available for 6 sDDLPS patients showed 2 local recurrences, treated with re-excision and radiation therapy, with all disease-free at last follow-up (5-126 months). Of the 7 secondary cases, 2 had ongoing disease after multiple recurrences, 1 was disease-free, and all 4 with cutaneous metastasis died of disease (follow-up range: 24-263 months). CONCLUSION: These findings emphasize the importance of distinguishing between primary sDDLPS and secondary lesions due to their distinct prognoses. Metastasis or superficial extensions from deep DDLP correlate with a considerably worse prognosis than those originating in superficial tissues.

Immunohistochemistry Update in Dermatopathology and Bone and Soft Tissue Pathology.

CONTEXT.­: Immunohistochemistry plays an important role in dermatopathology, particularly for melanocytic lesions and poorly differentiated malignancies. In the field of bone and soft tissue pathology, molecular methods remain the gold standard for diagnosis; however, immunohistochemistry targeting underlying molecular alterations represents a valuable screening tool, especially in areas with limited access to molecular testing. OBJECTIVE.­: To describe the utility and limitations of new and emerging immunohistochemical stains in the diagnosis of skin, soft tissue, and bone tumors. DATA SOURCES.­: A literature review of recently described immunohistochemical stains in the fields of dermatopathology and bone and soft tissue pathology was performed. CONCLUSIONS.­: Immunohistochemistry is an important adjunctive tool for select entities in dermatopathology and bone and soft tissue pathology, and it provides pathologists with valuable evidence of their behavior, underlying molecular alterations, and line of differentiation. Furthermore, immunostains targeting molecular abnormalities have the potential to replace current molecular methods. Many of these recently described stains demonstrate higher sensitivity and specificity; however, limitations and pitfalls still exist, and correlation with morphologic and clinical findings remains essential for diagnosis.

Cytologic features of hepatic YAP1-TFE3 rearranged epithelioid hemangioendothelioma.

Epithelioid hemangioendothelioma (EHE) is a rare vascular tumor of intermediate malignancy, often with indolent behavior. Though most cases have a characteristic WWTR1-CAMTA1 gene fusion, a subtype of EHE with YAP1-TFE3 fusions and a distinct morphology has recently been described histologically, but no cases of YAP1-TFE3 EHE have been described in the cytology literature. We herein report on a case of YAP1-TFE3 fusion associated EHE diagnosed on fine-needle aspiration and core biopsy of a liver mass in an 18-year-old male patient who presented with synchronous lung and liver involvement. We also discuss the differential diagnosis of EHE on cytology specimens.

Left Carotid Artery Thrombosis Due to Thromboangiitis Obliterans.

ABSTRACT: Thromboangiitis obliterans (TAO, Buerger disease) is a segmental, non-atherosclerotic vasculitis that causes occlusion of the small and medium sized vessels of the distal extremities. In rare cases, it can affect vessels in the gastrointestinal, cerebrovascular, coronary, and renal systems. The etiology of thromboangiitis obliterans is unknown, but there is a strong association with smoking in the development and the progression of the disease. We present the case of a 42-year-old homeless female smoker, who was found dead outdoors. Although originally suspected to be a possible trauma-related death, autopsy revealed a thrombus in her left carotid artery, which caused an acute cerebral infarction. It was concluded that thromboangiitis obliterans, likely precipitated by smoking, was the cause of the thrombosis and subsequent death.

Histiocyte-rich rhabdomyoblastic tumor: a report of two cases and a review of the differential diagnoses.

Histiocyte-rich rhabdomyoblastic tumor is a recently described skeletal muscle neoplasm of uncertain malignant potential, characterized by slow growth, a fibrous capsule containing peripheral lymphoid aggregates, spindle-to-epithelioid cells with a rhabdomyoblastic immunophenotype, and a dense histiocytic infiltrate. It most commonly arises within the muscles of the lower legs and trunk in young-to-middle-aged men, and initial reports suggest indolent behavior. In this paper, we present two additional cases of histiocyte-rich rhabdomyoblastic tumor with similar clinicopathologic features and discuss the differential diagnosis including its overlap with inflammatory leiomyosarcoma.

Correction to: Histiocyte-rich rhabdomyoblastic tumor: a report of two cases and a review of the differential diagnoses.

The given name of the co-author of the article mentioned above was incorrectly spelled. The correct name should have been "Melanie Bourgeau" instead of "Melanine Bourgeau." The original article has been corrected.