Related Experiment Videos
Retroperitoneal sclerosing PEComa with melanin pigmentation and granulomatous inflammation-a rare association within
Bharat Rekhi1, Mukund Sable, Sangeeta B Desai
1Department of Pathology, Tata Memorial Hospital, Parel, Mumbai, India.
Abstract:
PEComa, defined as a perivascular epithelioid cell tumor, displays a wide clinicopathological spectrum. Lately, a sclerosing PEComa has been identified as its distinct variant, but with limited documentation, in view of its rarity. Herein, we describe an uncommon case of a 53-year-old lady, who was referred to us with pain abdomen. Radiological imaging disclosed a well-defined, hypodense retroperitoneal mass. The excised tumor was a round, encapsulated soft tissue mass measuring 7 cm with a tan-brown cut surface. Microscopy showed uniform, epithelioid cells with clear cytoplasm, focal melanin pigmentation and mild nuclear atypia, arranged in sheets and nests around capillary-sized vessels in a dense sclerotic stroma. Additionally, co-existing epithelioid granulomas were noted. On immunohistochemistry (IHC), tumor cells were diffusely positive for HMB45; focally for desmin and smooth muscle actin (SMA), while negative for EMA, CD10, S100-P, Melan A, CD34, AMACR and CK MNF116. This case reinforces sclerosing PEComa as an uncommon, but a distinct clinicopathological entity and exemplifies diagnostic challenge associated with it; necessitating application of IHC markers for its correct identification. Presence of melanin pigment and granulomatous inflammation in the present tumor constitute as novel histopathological findings in a sclerosing PEComa.
Insights
This report details a rare case of sclerosing perivascular epithelioid cell tumor (PEComa), a distinct variant presenting diagnostic challenges. Novel findings include melanin pigment and granulomatous inflammation, highlighting the need for immunohistochemistry in diagnosis.
Area of Science:
- Oncology
- Pathology
- Rare Tumors
Background:
- Perivascular epithelioid cell tumors (PEComas) encompass a diverse group of neoplasms.
- Sclerosing PEComa is a rare variant with limited documented cases, posing diagnostic difficulties.
Observation:
- A 53-year-old female presented with abdominal pain due to a retroperitoneal mass.
- Histopathology revealed a sclerotic tumor with epithelioid cells, focal melanin pigment, and co-existing epithelioid granulomas.
- Immunohistochemistry confirmed tumor cells positive for HMB45, focally for desmin and SMA, and negative for other markers.
Findings:
- The case highlights sclerosing PEComa as a distinct clinicopathological entity.
- Melanin pigment and granulomatous inflammation are identified as novel histopathological features in this sclerosing PEComa.
- Immunohistochemistry is crucial for accurate diagnosis of this rare tumor.
Implications:
- This case expands the understanding of sclerosing PEComa's histopathological spectrum.
- Accurate diagnosis of rare tumors like sclerosing PEComa requires comprehensive histopathological evaluation and IHC.
- Further research is warranted to elucidate the pathogenesis and clinical behavior of sclerosing PEComa.
