Cytologic diagnosis of recurrent medullary thyroid carcinoma with oncocytic change twenty‐one years post‐thyroidectomy: Case report and review of the literature

Abstract

A 66-year-old woman presented 21 years prior with diarrhea and elevated serum calcitonin levels. The left lobe of the thyroid was aspirated but specimen was unsatisfactory. Nevertheless, based on the radiological and clinical impressions, the patient underwent total thyroidectomy and the histologic examination established the diagnosis of medullary thyroid carcinoma (MTC). Approximately 5 years later, the patient had a recurrence of the disease and underwent a neck lymph node dissection, which showed metastatic MTC in a lymph node. Sixteen years later, the patient presented with left neck mass detected by ultrasound in the area of thyroid bed. Fine needle aspiration (FNA) of this area was performed and the FNA diagnosis was consistent with oncocytic variant of MTC. This case illustrates a first report of this uncommon variant of MTC diagnosed by FNA cytology of the thyroid bed.

Oncocytic Variant of Medullary Thyroid Carcinoma: A Rare Case of Sporadic Multifocal and Bilateral RET Wild-Type Neoplasm with Revision of the Literature

“…Furthermore oncocytic variant of MTC has been invariably reported as a single lesion in contrast with the multifocal and bilateral neoplasia reported here. Tranchida and colleagues 16 described a recurrence in thyroid bed of medullary thyroid carcinoma in a patient, which underwent total thyroidectomy 20 years earlier. The relapsing mass showed an oncocytic differentiation that was lacking in the previous tumor.…”

Oncocytic Variant of Medullary Thyroid Carcinoma

“…Among these cases, one had an FNAB diagnosis as suspicious for follicular neoplasm-as we mentioned above, this would be the first entity in the differential diagnosis-and the other case had a lymph node FNAB diagnosis as an oncocytic variant of MTC in a patient who had thyroidectomy and diagnosed as MTC 5 years ago [5,9]. To the best of our knowledge, this is the first reported case of oncocytic variant of MTC diagnosed on FNA and confirmed with surgical pathology in the literature.…”

“…Oncocytic variant of MTC was first coined by Harach and Bergholm [3] in 1988, and a year later, Dominguez-Malagon et al [4] described the major criterion for the diagnosis, where 60-70 % of the cells should be oncocytic. Since then, a very limited number of cases have been reported in the literature [4,5]. Oncocytic cells have very unique molecular biologic features; abundant mitochondrial hyperplasia drives this special phenotype with a large eosinophilic, well-defined cytoplasm and eccentrically located round-to-oval nuclei and prominent nucleoli that can be seen in various organs including the thyroid [6].…”

“…Any misdiagnosis will cause delays in aggressive surgery or other modalities of therapy. Depending on the size of the tumor, total thyroidectomy and accompanying bilateral central/lateral lymph node dissection are the treatment of Table 1 Review of the literature Tranchida et al [5] H a r a c he ta l . [ 3] Dominguez et al [6] Desai et al [10] Raikhlin et al [11] Chettyetal.…”

Calcitonin Expression in the Metastatic Tissue of Medullary Thyroid Carcinoma

“…Oncocytic variant of MTC seen in the recurrent tumor has been documented in the literature to represent a further step in tumor progression and may be indicative of a poor prognosis. [16] But regarding the absence of calcitonin expression in the metastatic tissue of MTC, no references have been found. Thus we postulated two possible mechanisms for the absence of calcitonin expression in the metastatic tissue of medullary thyroid carcinoma: the first one is that the potential for metastasis increases as cancer cells lose their ability to secrete calcitonin during dedifferentiation, and the second explanation is that the secondary environment (metastatic site) may have disabled the cancer cells' ability to secret calcitonin.…”