ASPIRATION CYTOLOGY OF MALIGNANT NEOPLASMS ASSOCIATED WITH GRANULOMASAND GRANULOMA-LIKE FEATURES - DIAGNOSTIC DILEMMAS

BACKGROUND. Malignant lymphomas and solid tumors that mimic or are ass ociated with epithelioid granulomas are widely recognized in surgical pathology, but have received little attention in the cytopathology lit erature. In this study the authors present their experience with six s uch cases in which the presence of granulomas or granuloma-like featur es posed a diagnostic difficulty on fine-needle aspiration cytology (F NAC). METHODS. Clinical data, FNAC, and follow-up surgical specimens f rom six patients presenting with neck masses were reviewed. RESULTS, O nly one case was diagnosed confidently as metastatic squamous cell car cinoma with an extensive granulomatous response; the other five were i nterpreted as ''atypical'' with descriptive cytology and a differentia l diagnoses including granulomatous inflammation, in addition to a cav eat of ''cannot exclude malignancy.'' Biopsy studies in these cases we re recommended in view of the atypical cytologic findings and strong c linical suspicion of malignancy in each case. The histologic findings in two cases revealed Hodgkin's disease with exuberant granulomatous r esponse. The remaining three cases were found to be malignant neoplasm s with epithelioid morphologic features and included one example each of diffuse large cell lymphoma, anaplastic carcinoma of the thyroid, a nd lymphoepithelial carcinoma. CONCLUSIONS, Malignancies associated wi th granulomas and tumor cells mimicking epithelioid histiocytes may be difficult to diagnose accurately on FNAC. The cytologic differential diagnosis of a ''granulomatous'' process should include malignant neop lasms. Excisional biopsy studies may be required for definitive diagno sis. (C) 1998 American Cancer Society.