FINE-NEEDLE ASPIRATION CYTOLOGY OF MALACOPLAKIA OF THE THYROID - A CASE-REPORT

BACKGROUNDS: Malacoplakia was first describe dy Michaelis and Gutmann in 1902 and further characterized by Von Hansemann, who coined the ter m malacoplakia to describe the soft, yellow-tan, raised plaques he enc ountered in a case involving the urinary bladder.(11) CASE: Fine needl e aspiration cytology of a case of malacoplakia of the thyroid gland w as performed on a 60-year-old woman. Fine needle aspiration demonstrat ed histiocytes with abundant granular cytoplasm that were eosinophilic with hematoxylin-eosin stain. Many of the cells contained numerous ro und, regular-appearing inclusions, which ranged in size from 4 to 10 m u m in diameter. Many of these inclusions demonstrated the characteris tic concentric appearance of Michaelis-Gutmann bodies. The inclusions were strongly positive for periodic acid-Schiff stain and stained weak ly with Von Kossa stain. Clinically and radiologically the lesion mimi cked a malignant neoplasm by virtue of its large size and destruction of adjacent cervical vertebrae. The diagnosis was ascertained only aft er surgical excision. CONCLUSION: This is the first report of fine nee dle aspiration cytology of malacoplakia of the thyroid. The case demon strates how difficult it may be to diagnose this rare entity, regardle ss of its characteristic features. It also underscores the point that malacoplakia may occur anywhere in the body and should always be consi dered when round, concentric intracytoplasmic inclusions are seen with in histiocytes.