Myxofibrosarcoma: Cytomorphologic Findings and Differential Diagnosis on Fine Needle Aspiration

Abstract

Objective: To analyze the cytomorphologic findings of myxofibrosarcoma (MFS) on fine needle aspiration (FNA) and examine the differential diagnoses. Study Design: A retrospective review was undertaken of material from 22 patients with an FNA procedure of their tumor prior to resection. A tally was performed of all the features known in the literature, including myxoid matrix, spindle cells, nuclear pleomorphism, curvilinear vessels, and multinucleated cells. A review of the literature was also performed to elucidate any advances in the use of morphology and other modalities to deconvolute the challenging differential diagnosis. Clinicoradiologic characteristics and immunostaining were also analyzed and correlated. Results: FNA diagnoses included high-grade sarcoma (32%), recurrent MFS (23%), spindle cell neoplasm (18%), indeterminate-grade sarcoma (14%), low-grade sarcoma (9%), and pleomorphic adenoma (4%). Of the cases available for morphologic review, myxoid matrix was the most frequent observation (88%), followed by spindle cells (82%), nuclear pleomorphism (76%), multinucleated cells (71%), and curvilinear vessels (65%). Myxoid matrix, spindle cells, and nuclear pleomorphism were very often concomitant observations. Conclusion: MFS demonstrates characteristic albeit nonspecific morphological findings and can overlap morphologically with other clinically significant entities based on FNA material.

Comparative cytological and histological assessment of 828 primary soft tissue and bone lesions, and proposal for a system for reporting soft tissue cytopathology

“…In the current study these were benign nerve sheath tumours, fibrous histiocytomas and myxomas vs sarcomas with low‐grade cytomorphological features such as low‐grade MPNST, synovial sarcomas, low‐grade myxofibrosarcomas and LGFMS. Diagnostic pitfalls are based on morphological overlap between the different tumour entities and their morphological variations, as described before 22–25 . Another problematic group encompassed lipomas and ALT.…”

Myxoid Soft Tissue Tumors: A 20-Year Experience on Fine Needle Aspiration with Application of the Proposed WHO Reporting System for Soft Tissue Cytopathology

“…Myxofibrosarcoma was previously regarded as a myxoid variant of malignant fibrous histiocytoma, now known as undifferentiated pleomorphic sarcoma [24]; however, myxofibrosarcoma is currently recognized as a separate entity and defined by variable myxoid matrix, cellular atypia, and curvilinear vessels [23]. The cytomorphologic features of myxofibrosarcoma in the literature are heterogenous, but they all demonstrated myxoid stroma, variable cytologic atypia depending on the histologic grade, and curvilinear or arborizing vessels [25][26][27][28][29]. The frequency of these features was variable in the literature.…”

Hypercellular round cell liposarcoma: A comprehensive cytomorphologic study and review of 8 cases

“…Thus, MFS and ESCMS were the two most important myxoid sarcomas included in the differential diagnosis. [15161718192021]…”

“…The background matrix in MFS had a diffuse granular quality spread over the entire smear instead of clumps and fragments in RCL [Figure 2d]. [131516171819] The more cellular uniformity, occasional presence of lipoblasts, plexiform thin capillaries instead of thick, and ANAC can rule out MFS [Figure 2e]. …”