Objective To examine genotypic and clinical differences between encapsulated, non-encapsulated and diffuse follicular variant of papillary thyroid carcinoma (EFVPTC, NFVPTC, diffuse FVPTC), in order to characterize the entities and identify predictors of their behavior. Design Retrospective chart review and molecular analysis. Setting Referral center of a university hospital. Patients The pathology of 484 consecutive patients with differentiated thyroid cancer who underwent surgery by the 3 members of the NYU Endocrine Surgery Associates from January 1, 2007 to August 1, 2010 was reviewed. Forty-five patients with FVPTC and in whom at least 1 central compartment lymph node was removed were included. Main Outcome Measures Patients with FVPTC were compared in terms of age, gender, tumor size, encapsulation, extrathyroid extension, vascular invasion, central nodal metastases, and the presence or absence of mutations in BRAF, H-RAS 12/13, K-RAS 12/13, N-RAS 12/13, H-RAS 61, K-RAS 61, N-RAS 61 and RET/PTC1. Results No patient with EFVPTC had central lymph node metastasis and in this group, 1 patient (4.5%) had a BRAFV600E mutation and 2 patients (9%) had RAS mutations. Of the patients with NFVPTC, 0 had central lymph node metastasis (p=1) and 2 (11%) had a BRAFV600E mutation (p=0.59). Of the patients with diffuse FVPTC, all had central lymph node metastasis (p=0.0001) and 2 (50%) had a BRAFV600E mutation (p=0.12). Conclusions FVPTC consists of several distinct subtypes. Diffuse FVPTC seems to present and behave in a more aggressive fashion. It has a higher rate of central nodal metastasis and BRAFV600E mutation in comparison to EFVPTC and NFVPTC. Both EFVPTC and NFVPTC behave in a similar fashion. The diffuse infiltrative pattern and not just presence/absence of encapsulation seems to determine the tumor phenotype. Understanding the different subtypes of FVPTC will help guide appropriate treatment strategies.

No abstract

Summary Multifocal papillary thyroid carcinoma (PTC) is common and the number of tumor foci rarely exceeds ten. The mechanism of multifocal disease is debated, with the two main hypotheses consisting of either intrathyroidal metastatic spread from a single tumor or independent multicentric tumorigenesis from distinct progenitor cells. We report the case of a 46-year-old woman who underwent total thyroidectomy and left central neck lymph node dissection after fine-needle aspiration of bilateral thyroid nodules that yielded cytological findings consistent with PTC. Final pathology of the surgical specimen showed an isthmic dominant 1.5 cm classical PTC and over 30 foci of microcarcinoma, which displayed decreasing density with increasing distance from the central lesion. Furthermore, all malignant tumors and lymph nodes harbored the activating BRAF V600E mutation. The present case highlights various pathological features that support a mechanism of intraglandular spread, namely a strategic isthmic location of the primary tumor, radial pattern of distribution and extensive number of small malignant foci and BRAF mutational homogeneity. Learning points: Multifocal papillary thyroid carcinoma (PTC) is commonly seen in clinical practice, but the number of malignant foci is usually limited to ten or less. There is no clear consensus in the literature as to whether multifocal PTC arises from a single or multiple distinct tumor progenitor cells. Strategic location of the dominant tumor in the thyroid isthmus may favor intraglandular dissemination of malignant cells by means of the extensive lymphatic network. An important pathological finding that may be suggestive of intrathyroidal metastatic spread is a central pattern of distribution with a reduction in the density of satellite lesions with increasing distance from the dominant focus. PTCs originating from the isthmus with intraglandular metastatic dissemination behave more aggressively. As such, a more aggressive treatment course may be warranted, particularly with regard to the extent of surgery.

This case presents a hydatid cyst of the thigh in a 57-year-old patient born and raised in rural Montenegro. He presented with a painful erythematous mass on the lateral aspect of the right thigh at the site of a previous cystic mass resection 13 years earlier. Complete surgical resection was conducted, histopathology revealed laminated membranes and polymerase chain reaction was positive for Echinococcus granulosus. Primary musculoskeletal hydatidosis is a rare entity and diagnosis is challenging. Any cystic lesion in a patient from an endemic area should raise the possibility of echinococcosis, regardless of anatomic location. The key aspects of diagnosis, albendazole treatment and surgical management are discussed.

No abstract