Medullary thyroid carcinoma (MTC) is a thyroid malignancy originating from C cells. To date, serum calcitonin measurement and fine-needle aspiration biopsy (FNAB) have been prominent diagnostic approaches to these lesions. Although an elevated serum calcitonin level strongly suggests the presence of MTC, this examination cannot identify the origin of the calcitonin overexpression, especially in patients demonstrating multiple thyroid nodules. For the treatment planning, it is important to know which nodule is MTC, especially in nonhereditary MTC. In this study, we propose calcitonin measurement in the washout of FNAB needles after sampling each tumor (FNAB-CT) as a new approach to diagnosis of MTC. We performed FNAB-CT for five MTC cases. Although only one of these cases was definitively diagnosed as having MTC by FNAB cytology, FNAB-CT values ranged from 17,000 to 560,000 pg/mL, which were exceedingly higher than those of 11 controls (seven papillary carcinomas, two adenomatous nodules, one chronic thyroiditis, and one normal thyroid), which showed values ranging from <10 to 67 pg/mL. In patients with MTC, FNAB-CT values were 74 to 1888 times greater than serum calcitonin values. These findings suggest that FNAB-CT can be an additional approach to diagnosis of MTC.

abstract. Cribriform-morular variant (CMV) is a comparably rare histological subtype of papillary thyroid carcinoma (PTC). This can be associated with familial adenomatous polyposis (FAP) due to APC gene mutations. In this study, we investigated the difference in the biological characteristics between FAP-associated and sporadic CMV. Between 1991 and 2010, 32 patients with CMV were treated in Kuma Hospital. Thirty-one of these underwent initial surgery for CMV in Kuma Hospital. Twelve patients were FAP-associated and the remaining 19 were sporadic CMV. All patients were female. Tumors of FAP-associated CMV were more frequently multiple than those of sporadic CMV. Patient age and tumor size did not differ between the two groups. Of 12 FAP-associated CMV, 5 were detected by thyroid nodule (thyroid precedent group) and 7 were detected by FAP (polyposis precedent group) as an initial manifestation. Patient age was younger and tumor size was smaller in the polyposis group than in the thyroid nodule group. All patients lacked extrathyroid extension on intraoperative finding and were node-negative on pathological examination. To date, two patients with FAP-associated CMV who initially underwent hemithyroidectomy (one in Kuma Hospital and one in another hospital) showed recurrence to the remnant thyroid during follow-up. None of the patients showed recurrence to other regions or died of carcinoma. Taken together, CMV is considered an indolent disease in our series. FAP-associated CMV showed multiple tumors more frequently than sporadic CMV. Total thyroidectomy is recommended for FAP-associated CMV, but extensive lymph node dissection is not necessary.

We present a case of skin metastasis from follicular thyroid carcinoma which developed on the scalp of a 72-year-old man. The lesion was noticed 1 month after a surgical excision of the primary thyroid carcinoma and gradually enlarged during the past 11 months. A biopsy from the nodule showed mostly well-differentiated thyriod follicular structures with colloid material. Tumor cells showed mild variation of nuclear size and shape in almost all areas. We performed immunohistochemistry using antithyroglobulin antibody, which established the diagnosis of a metastatic lesion from thyroid follicular carcinoma. Total thyroidectomy and I radiotherapy were performed. No further metastasis has been discovered during the last 18 months.

Widely invasive follicular thyroid carcinoma (wi-FTC) is regarded as having an aggressive character and a dire prognosis, but it has not been known whether all wi-FTCs have a dire prognosis. Herein we retrospectively analyzed the cases of 133 patients with wi-FTCs to determine the prognostic significance of vascular invasion and cell-proliferation activity based on the Ki-67 labeling index (LI). Of the 119 patients without distant metastasis (M0), 11 (9.2%) showed recurrence during the postoperative follow-up. In a univariate analysis, the recurrence-free survival (RFS) rates of the M0 patients with vascular invasion and those with a Ki-67 LI ≥5% were significantly poorer (p = 0.0013 and p = 0.0268, respectively) than those of the patients without vascular invasion or with a Ki-67 LI <5%. Other clinicopathological factors such as patient age, gender, tumor size, and oxyphilic tumor were not significantly related to the patients' RFS. In a multivariate analysis, positive vascular invasion independently affected the RFS (p = 0.0133), but Ki-67 >5% did not (p = 0.1348). To date, only five patients have died of their thyroid carcinoma; four cases were M1. In conclusion, although M0 wi-FTC generally has a favorable prognosis, cases with positive vascular invasion or a high Ki-67 LI are likely to recur, and careful postoperative follow-up is necessary.