Year: 2025
Type: article
Study design: Case Report
Abstract: While plasma cell neoplasms typically display overt plasmacytoid morphology, unusual histologic variants can mimic soft tissue tumours such as solitary fibrous tumour (SFT). Critically, SFTs lack plasmacytoid differentiation, which is a key distinguishing feature. We present two cases in which plasma cell neoplasms mimicked SFT histologically, underscoring the importance of recognizing this pitfall.Case 1: A L1-L2 lytic lesion in a 46-year-old woman was diagnosed on biopsy as SFT due to the presence of a "patternless" spindle-cell proliferation with hemangiopericytoma-like vessels. Excision revealed focal plasmacytoid cells, a feature that is not in keeping with SFT. This prompted immunohistochemistry (IHC) testing, which showed that the tumour cells were CD138+ plasma cells, confirming a plasma cell neoplasm.Case 2: A 41-year-old man presented with a L2 fracture, that on histology exhibited a vascular tumour with staghorn vessels and diffuse plasmacytoid morphology. Further evaluation with IHC (CD138+) and serum analysis led to a diagnosis of multiple myeloma.These cases demonstrate that plasmacytoid morphology, even if focal, should prompt consideration of plasma cell neoplasms. Pathologists must recognize this distinction, particularly in vascular-rich spindle-cell lesions, as misdiagnosis delays appropriate treatment.
Source: Journal of Diagnostic Pathology
Institution: National Hospital of Sri Lanka
Language: English
Subfield: Hematology
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W4412507445