To date, we have studied 89 palpable lesions of the scrotum, testicle, and epididymis using fine-needle aspiration cytology (FNAC). Cystic lesions (48.3%) and inflammatory pathology (25.8%) were the most frequent findings. Tumors accounted for 11.2% of results, with a slight predominance of the malignant varieties. In this article, we describe the cytopathology of the main entities and discuss the principal problems of differential diagnosis, especially among inflammatory processes, seminomas, and embryonal carcinomas. The cytopathological pattern of the neoplasias is highly characteristic, and this permits their diagnosis with great precision. FNAC is essentially nontraumatic and easy to carry out, but it requires considerable practice in its execution and in the interpretation of the aspirates. We believe FNAC to be the technique of choice for the study of the pathology of the scrotal content, and we think that it should be employed on the patient's very first visit. The main advantage of FNAC is avoiding delays in diagnosis.

We describe one case of Rosai-Dorfman disease (RDD) localized in the breast and one case of breast malacoplakia (MPK) both diagnosed by fine-needle aspiration cytology (FNAC). In RDD the cytologic features were lymphocytophagocytosis, large histiocytes with slight nuclear atypia, and lymphohistiocytic aggregates in a polymorphous background which included frequent plasma cells. In MPK the key diagnostic feature was the presence of Michaelis-Gutmann bodies (M-G bodies), in various stages of evolution, intermingled with vacuolized medium-sized histiocytes, other inflammatory cells, and debris. Pap staining is the technique of choice to show lymphocytophagocytosis and M-G bodies and there is no need to resort to special staining methods. RDD and MPK share a common cytologic background: the presence of numerous benign reactive histiocytes, either engulfing apparently intact lymphocytes, or phagocytizing M-G bodies. The cytologic findings seen in both cases suggest that the presence of histiocytes in a breast aspirate is far from being nonspecific and can represent an important lead to disparate diseases such as RDD and MPK.

The present study shows a good correlation between GICS categories and histological diagnosis.