Atypical spindle cell/pleomorphic lipomatous tumour (ASPLT): A report of three FNA cases and comparison with spindle cell/pleomorphic lipoma cytopathology

Abstract

AbstractIntroductionAtypical spindle cell/pleomorphic lipomatous tumour (ASPLT) is an infrequently appreciated benign lipomatous neoplasm newly accepted into the most recent WHO classification of soft tissue tumours.Materials and MethodsOur cytopathology files were searched for examples of ASPLT and spindle cell/pleomorphic lipoma (SCPL) having histopathological verification. Conventional fine needle aspiration (FNA) biopsy smears were performed using standard techniques.ResultsEleven patients including three cases of ASPLT and eight of SCPL (M:F = 4.5:1; age range: 39‐97 years, mean age = 60 years) met the inclusion criteria. FNA biopsy sites included extremity (5, 45%), trunk (3, 27%), and head/neck (3, 27%). All aspirates were from primary neoplasms. FNA diagnoses of ASPLT cases were spindle cell lipomatous neoplasm, fibrotic low‐grade SC neoplasm, and myxoid lipomatous neoplasm. Eight SCPL cases were diagnosed as spindle cell neoplasm (3), spindle cell lipoma (SCL) (1), pleomorphic lipoma (1), suspicious for SCL (1), benign adipose tissue (1), and benign spindle cells and connective tissue (1). Ancillary testing in two ASPLT cases showed positive CD34 and negative MDM2 immunostain in one, and negative FISH results for MDM2 and DDIT3 in another.ConclusionASPLT is a novel lipomatous neoplasm simulating primarily SCPL and atypical lipoma/well‐differentiated liposarcoma. Diligent cytomorphological observation, clinical information, and ancillary testing may allow for its specific recognition using FNA biopsy.