Background: Oncocytic cell neoplasm of the thyroid is currently recognized as a histological entity, but doubts still exist about its clinical and evolutionary categorization. Controversies concern occurrence and frequency of malignant forms, natural history and therapeutic strategies.
Materials and methods: The authors report six cases of Hürthle cell tumor. Five cases were adenoma, one was carcinoma. Morpho-functional pre-operative evaluation and inter-operative histopathological test were performed in all patients. One patient underwent lobectomy (absence of unusual characteristics of the adenoma Hürthle cell) and five underwent total thyroidectomies (1 carcinoma). All patients were treated with suppressive hormonal therapy.
Results: No mortality and morbidity was recorded. All patients are undergoing follow-up (adenomas: average 64.2 months; carcinoma: 132 months) and none of them show recurrent symptoms.
Discussion: Hürthle cell tumors can be diversified in adenoma and carcinoma. Almost all reports classify oncocytic nodules as malignant when capsular and/or vascular invasion is present or when there is peri-thyroid tissue infiltration or lymphatic or hematic metastases. A clear differentiation between adenoma and carcinoma is determined by a histological test. Also an intra-operative histopathological analysis is sometimes unable to show minimal signs of invasion. Conflicting observations about the biological behaviour of Hürthle cell neoplasm lead to different therapeutic strategies. The authors believe lobectomy is the treatment of choice when a clear histological diagnosis of adenoma has been made. When carcinoma is diagnosed or when doubts exist after intraoperative histological test, the authors recommend total thyroidectomy followed by scintigraphic test and preventive radio-active therapy. All patients should be treated with suppressive hormonal therapy and undergo periodic check-ups.