Atypical Spindle Cell Lipomatous Lesion Resected From Patient With History of CLL

Lumbar paraspinal atypical spindle cell/pleomorphic lipomatous tumor: A report of a rare case

The atypical spindle cell/pleomorphic lipomatous tumor (ASPLT) was classified as a new tumor by the World Health Organization (WHO) in 2020. The tumor is benign and commonly occurs in the limbs. Paraspinal presentations are rare. A 38-year-old man presented at our clinic complaining of sudden onset back pain. No neurological deficit was found. The magnetic resonance imaging (MRI) revealed a well-defined heterogeneous mass in the left psoas muscle, from L1 to L3 extending over the L1 and L2 neuroforamen. The tumor was totally excised. Pathology led to an ASPLT diagnosis. Clinical symptoms improved and there was no postsurgical neurological deficit. This case of ASPLT, located in an uncommon location and present an unusual cluster of symptoms, could be treated by surgical excision, usually the first-treatment strategy. Totally, removal was achieved because there was a clear morphological margin. The risk of metastatic dissemination was minimal, though there remains a nonnegligible risk of local recurrence.

Case report: Atypical spindle cell/pleomorphic lipomatous tumor masquerading as a myxoid liposarcoma or intramuscular myxoma

Atypical spindle cell/pleomorphic lipomatous tumors (ASPLTs) were recently categorized as benign lipomatous tumors. However, accurate and complete preoperative diagnosis of ASPLTs may be difficult. Furthermore, diagnosis based on magnetic resonance imaging (MRI) findings is uncertain because of the varying ratios of the fat component within the tumor. Here, we report a case of ASPLT masquerading as a myxoid tumor. Although MRI findings were consistent with a myxoid liposarcoma, needle biopsy findings suggested a myxoma, and we performed marginal resection. Histopathological findings revealed infiltrating spindle cells with atypia. In addition, immunohistochemistry (IHC) showed positive staining for CD34 and heterogeneous retinoblastoma deficiency, and fluorescence in situ hybridization (FISH) showed no amplification of mouse double minute 2 homolog and no rearrangement of FUS or EWSR1. When MRI and histopathological findings suggest a myxoid tumor, IHC and FISH should be considered and performed for a precise and accurate diagnosis.

An Atypical Pleomorphic Lipomatous Tumor Presenting As Groin Mass

Cutaneous tumors with adipocyte differentiation are frequently excised by surgeons in their daily clinical practice and sometimes less common histological diagnoses arise. Knowledge of different pathological entities and their natural history is essential for better patient management.

Atypical spindle cell/Pleomorphic lipomatous tumor (ASPLT) is a recent group included in the WHO classification. We report a case of a middle-aged man with an atypical pleomorphic lipomatous tumor in an unusual location.