A Squamous Cell Carcinoma and a Malignant Fibrous Histiocytoma Developing in a Patient with a Mature Cystic Teratoma.

We present a very rare case of malignant transformation of a benign mature cystic teratoma. The pathology report revealed malignant transformation of both the epithelial and sarcomatous elements of a benign dermoid cyst. To the best of our knowledge, this appears to be the third case of a malignant fibrous histiocytoma and a squamous cell carcinoma developing from a mature cystic teratoma. Malignant transformation of a dermoid cyst is usually diagnosed postmenopausally, but our patient was premenopausal. The etiology and prognosis of malignant transformation of this benign condition remain unknown.

Histopathologic diagnosis of thyroid tuberculosis.

BACKGROUND: Thyroid tuberculosis is rarely encountered. Due to the absence of specific signs and symptoms, the diagnosis is difficult without histopathologic examination of surgical material. In this study, we aim to present histopathologic findings of our patients with thyroid tuberculosis. METHODS: We retrospectively reviewed 800 thyroidectomy specimens from the pathology laboratories of two medical centers that were obtained over a 5-year period. We reviewed clinical and laboratory data, fine-needle aspiration cytology smears, and 4-microm formalin-fixed paraffin-embedded hematoxylin-eosin sections and Erlich Ziehl Nelsen-stained sections of granulomatous thyroiditis. RESULTS: We found nine cases of granulomatous thyroiditis and detected five cases of thyroid tuberculosis. Thyroid ultrasound revealed hypoechoic nodules ranging between 1.3 and 2.5 cm in all patients with thyroid tuberculosis. Fine-needle aspiration cytology smears, which showed thyrocytes, macrophages, and lymphocytes with a colloid background, were nonspecific. Microscopic examination of all thyroids revealed granulomas of different sizes, which were composed of Langhans' giant cells, epithelioid histiocytes, and lymphocytes around caseation necrosis. In Erlich Ziehl Nelsen-stained sections of three cases, bacilli were seen. Bacilli were identified in the microbiology culture of the remaining two patients. CONCLUSIONS: Thyroid tuberculosis is diagnosed by histopathologic examinations and microbiologic cultures. When granulomatous thyroiditis is encountered, tuberculosis should be kept in mind and Erlich Ziehl Nelsen staining should be performed for prompt diagnosis.