Phyllodes Tumor, A Cytomorphologic Study of 17 Cases with Histologic Correlation.

Background & Objective: Phyllodes tumor (PT) is a rare fibroepithelial tumor of the breast exhibiting varied clinicopathologic behavior, ranging from benign to borderline to frankly malignant, based on the presence of infiltrative margins, stromal overgrowth, stromal atypia, cellularity, and mitotic activity. In this study, a detailed cytomorphological study of cases of PT with the clinical and histological correlation was performed.

Methods: A cytomorphological study of 17 cases of histologically proven PT diagnosed between Jan 2014 and July 2021 was done retrospectively. Relevant data including age at the time of diagnosis, the duration of illness, presenting symptoms, personal and family history, tumor size, tumor localization, and surgical procedure were obtained. A detailed cytomorphological assessment of stromal and epithelial components was performed, and further histological correlation was obtained for each case.

Results: Age of the patients ranged from 25 to 65 years old. The chief complaint was a palpable breast mass in all patients. The mean size of the lump was 11.86 cm. A complete cytohistological concordance was achieved among malignant cases. Stromal metaplasia was observed in only one case of benign phyllodes tumor, which was chondroid differentiation, and malignant heterologous component as fibrosarcomatous differentiation in one of the malignant PTs. Each of the benign and malignant phyllode tumors ductal carcinoma in situ (DCIS) of its epithelial component was seen in one case.

Conclusion: Phyllodes should be considered in differential diagnosing of any rapidly growing breast lump. Breast imaging has limited role in diagnosis of phyllode tumors. FNAC or trucut biopsy is mandatory in preoperative diagnosis. An extended follow-up is needed in all cases.