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Pseudoangiomatous stromal hyperplasia (PASH) is an uncommon lesion usually found in premenopausal women. Histologically, it is characterized by complex, anatomosing, empty slit-like spaces in a dense collagenous stroma. These pseudoangiomatous spaces are lined by monomorphic spindle cells of myofibroblastic differentiation. Cytological features of PASH are rarely discussed and reported, and may pose diagnostic challenge to surgical pathologists. Two cases of PASH are reported with emphasis on the FNAC features and cytologic differentiation from other benign fibroepithelial lesions.

We report the cytology findings of a rare case of myxoid leiomyosarcoma of the uterus with intraabdominal dissemination. The cytology showed uniformly dispersed spindly to polygonal "epithelioid" tumor cells focally linked by background matrix. Spindly tumor cells attaching to and radiating from branching capillary structures were also present. Occasionally, scattered "signet-ring" cells were found, mimicking metastatic poorly differentiated adenocarcinoma. The background mucoid substance was more conspicuous in the cell block sections. Gross and histologic examination of the surgical specimen revealed a large uterine leiomyosarcoma with prominent myxoid change. Ultrastructural study showed that the "signet-ring" appearance was mainly due to degenerative cytoplasmic change with ballooning of mitochondria, dilatation of endoplasmic reticulum, and elevation of outer nuclear membrane. In contrast to other spindle cell malignancies such as sarcomatoid mesothelioma, sarcomatoid carcinoma, or malignant melanoma, true sarcoma cells in general carry a distinctive cytologic appearance in washing/effusion fluid. In a correct clinical setting, the peculiar association with mucoid matrix and absence of classic lipoblasts should also raise the suspicion of metastatic myxoid leiomyosarcoma.