Pleomorphic liposarcoma: A clinicopathologic study of 20 FNA cases

Abstract

BACKGROUND Pleomorphic liposarcoma (PLPS) is the least common but most aggressive of all forms of liposarcoma (LPS). Its diagnosis relies on the recognition of pleomorphic lipoblasts (PLBs), whose numbers vary considerably. Because few large fine‐needle aspiration (FNA) biopsy studies exist, the authors review their experience with PLPS. METHODS The authors’ cytopathology files were searched for PLPS with histopathologic verification. FNA biopsy smears were performed via standard techniques. RESULTS Twenty cases from 20 patients (male/female ratio, 2.3/1; age range, 22‐77 years; mean age, 58 years) met the inclusion criteria. All had tissue confirmation. Biopsy sites included the following: thigh (11 [55%]), upper extremity (4 [20%]), axilla (2 [10%]), neck (1 [5%]), chest wall (1 [5%]), and mediastinum (1 [5%]). Aspirates were from primary (17 [85%]), locally recurrent (2 [10%]), and metastatic neoplasms (1 [5%]). The FNA diagnoses were PLPS (10 [50%]), myxofibrosarcoma (4 [20%]), LPS (2 [10%]), sarcoma (2 [10%]), and high‐grade malignant neoplasm (2 [10%]). Smears showed thick cell clusters and dissociated single forms. Pleomorphic, epithelioid, and bizarre cell/nuclear shapes were common. PLBs were absent, rare, or unnoticed in 45%. In 25%, smears dominated by myxoid stroma were diagnosed as high‐grade myxofibrosarcoma or myxoid LPS. Ancillary testing performed in 5 cases had limited diagnostic efficacy. CONCLUSIONS FNA biopsy of PLPS, although able to successfully recognize malignancy, suffers from a sampling bias due to an inability to capture or recognize PLBs in a significant proportion of cases secondary to the heterogeneous composition of this neoplasm.;

Apprenticeship and the art of making meaning in cytopathology

“…There is an apprenticeship that readers assume when encountering something such as the work that Wakely et al 1 have reported here. When an expert reports the method to diagnose a rare lesion, 2 things are assumed.…”

“…However, when trainees are ready to become attendings and to encounter things on their own, they shift their apprenticeship from the expert to the pathologic material itself. The work by Wakely et al 1 shows how we the readers might become apprentices of difficult sarcomas, as they have done. We may retrace their steps.…”

“…The work of Wakely et al 1 provides a masterclass in the cytopathologic diagnosis of pleomorphic liposarcoma via fine‐needle aspiration biopsy (FNAB). The straightforwardness of the article almost hides its elegance.…”

“…Why are these subjective perceptions so important as to venture into the realms of philosophy and literature? Wakely et al 1 argue that merely “categorizing aspirates under the general heading of ‘sarcoma or pleomorphic sarcoma’” is insufficient, and they “agree with experts” that “precise subclassification of ‘pleomorphic sarcoma’ remains necessary and desirable.” This declaration presumes a radical plasticity in both the perceptual abilities of the pathologist and the meaning attributed to the perceived qualities in a specimen. These new meanings are achieved by the new diagnostic strata available in anatomic pathology: from increasingly sophisticated biomarker testing, both molecular and otherwise, to the transhuman perceptions of artificial intelligence 9 .…”

“…Sufficient diagnostic material creates the conditions for the possibility of a specific diagnosis, which in turn creates the conditions for the possibility of treatment for the patient. Personally, I take the genealogy of the publications to which the work of Wakely et al 1 belongs as a call for cytopathologists to continually rededicate themselves to the performance and teaching of good biopsy technique. Learning to perform FNAB well requires tactile feedback, which can be simulated but not via teleconference.…”