Biological Behavior of Papillary Carcinoma of the Thyroid Including Squamous Cell Carcinoma Components and Prognosis of Patients Who Underwent Locally Curative Surgery

Thyroid carcinoma showing squamous differentiation throughout the entire lesion is diagnosed as squamous cell carcinoma of the thyroid (SCCT) in the WHO classification. This entity is a rare disease and shows a dire prognosis; however, squamous differentiation is more frequently detected in only a portion of papillary thyroid carcinoma. In this paper, we present our experience of 10 patients (8 primary lesions and 2 with recurrence in the lymph nodes) with papillary thyroid carcinoma having an SCC component (PTC-SCC). Only 3 of 8 primary lesions (38%) and none of the 2 recurrent nodes were preoperatively diagnosed as or suspected of having SCC components. All 10 patients underwent locally curative surgery. To date, 3 patients have died of carcinoma, and 2 had distant metastasis at diagnosis or had an undifferentiated carcinoma component. The other 7 are currently alive 5 to 43 months after diagnosis. Systemic adjuvant therapy after the detection of recurrence was effective for 2 patients. It is possible that some PTC-SCC patients without distant metastasis who undergo locally curative surgery can survive for a prolonged period and adjuvant therapies can be effective for local and distant recurrences

Prognosis of Patients with Papillary Thyroid Carcinoma Located in One Lobe Showing Lateral Node Metastasis in the Contralateral but Not Ipsilateral Compartment

Papillary thyroid carcinoma (PTC) frequently metastasizes to the lymph node in lateral compartment, which can often be detected on preoperative ultrasonography (N1b). However, PTC located in one lobe showing contralateral but not ipsilateral N1b is not common. We analyzed the clinicopathological features and prognosis of 13 patients with PTC limited in one lobe showing contralateral but not ipsilateral N1b. Sizes of the primary lesions ranged from 0.8 cm to 3.0 cm and only 2 tumors showed extrathyroid extension. Metastatic lateral node measured from 0.6 to 3.1 cm. Ten patients showed pathological central node metastasis and 5 had minute PTC lesions in the contralateral lobe. However, 3 patients did not show either of these. None of the patients have developed carcinoma recurrence or died of carcinoma to date. Taken together, PTC located in one lobe with contralateral but not ipsilateral N1b is rare and generally shows an indolent behavior. Although most patients had central node metastasis and/or minute PTC lesions in the contralateral lobe, it is also possible for carcinoma cells to metastasize directly from primary lesions to the contralateral lateral node. Total thyroidectomy with central node dissection and therapeutic MND of the contralateral compartment may be an acceptable surgical design and bilateral MND might not be mandatory