The usefulness of fine-needle aspiration biopsy (FNAB) for the histologic subtyping of specific sarcomas still is somewhat controversial but is becoming increasingly popular in the U.S.
To determine the accuracy and usefulness of FNAB in the differential diagnosis of myxoid sarcoma, the authors retrospectively reviewed 18 FNAB specimens (16 primary tumors, 1 local recurrence, and 1 metastasis) in 18 patients. The study sample included myxoid/round cell liposarcoma in six patients, myxofibrosarcoma in six patients, myxoid chondrosarcoma in five patients, and myxoid leiomyosarcoma in one patient.
All but one tumor were recognized correctly as malignant. With regard to primary tumors, a specific cytologic diagnosis was rendered in 13 of 16 patients (81%). Problematic areas included the diagnosis of high grade myxofibrosarcoma with minimal amounts of myxoid stroma, myxoid liposarcoma with a predominant round cell component, and the single case of myxoid leiomyosarcoma.
FNAB represents a valuable diagnostic tool for the differential diagnosis of myxoid sarcoma, especially myxofibrosarcoma, low grade myxoid liposarcoma, and myxoid chondrosarcoma. Due to its prognostic and therapeutic significance, the presence of a predominant round cell component in myxoid liposarcoma should be documented adequately. Other sarcomas (e.g., leiomyosarcoma) rarely may exhibit a prominent myxoid stroma and therefore should be considered in the differential diagnosis of adult myxoid sarcoma.