A rare case of the recurrent surgery for cribriform-morular variant of papillary thyroid carcinoma.

INTRODUCTION: The cribriform-morular variant of papillary thyroid carcinoma (CMV-PTC) is an uncommon subtype of PTC, and it is associated with familial adenomatous polyposis (FAP). PRESENTATION OF CASE: We describe a 32-year-old female who presented recurrent CMV-PTC with FAP. Surgery performed after the recurrent disease resulted in left recurrent laryngeal nerve palsy due to formation of strong scar after initial operation. The histopathological examination revealed the recurrent CMV-PTC without thyroid capsular invasion in remnant thyroid tissue of berry ligament. In addition, the immunohistochemical analysis showed that ß-Catenin was diffusely positive in both cytoplasm and nucleus in CMV-PTC tissue. CONCLUSION: Total thyroidectomy in CMV-PTC with FAP should be performed at initial surgery due to high recurrence.

Multifocality in a Patient with Cribriform-Morular Variant of Papillary Thyroid Carcinoma Is an Important Clue for the Diagnosis of Familial Adenomatous Polyposis.

Background: Cribriform-morular variant of papillary thyroid carcinoma (CMV-PTC) is a rare subtype of PTC, which occurrs predominantly in young women. This disease much more frequently presents in patients with familial adenomatous polyposis (FAP). FAP is an autosomal dominant inherited disease, which arises from germline mutations in the adenomatous polyposis coli (APC) gene. To clarify the distinctive clinical features of CMV-PTC, a comparison study was performed between familial types and sporadic types. Methods: Between 2007 and 2018, 15 CMV-PTC patients underwent thyroidectomy in Samsung Medical Center. The clinical features of these patients were retrospectively reviewed. Results: All patients were women with a median age of 26 years (range 17-46 years). The median maximum diameter was 1.0 cm (range 0.4-3.5 cm). All tumors underwent immunostaining and showed nuclear and/or cytoplasmic staining for ß-catenin. On ultrasonography, most nodules had benign-looking features (well-defined, hypoechoic, and oval to round shapes without calcification), but a few nodules had capsular invasion and taller than wide shape. On preoperative fine-needle aspiration cytology, five patients (33%) were diagnosed as CMV-PTC, nine (60%) as PTC, but one (7%) as follicular neoplasm or PTC-follicular variant. Six patients (40%) had FAP, and four of them had total colectomy due to FAP. Five of them had a family history of FAP or colon cancer, or thyroid cancer. Germline mutations in the APC gene were found in all six patients with CMV-PTC associated with FAP, and five of them had de novo mutations. All patients with FAP-associated CMV-PTC had multiple tumors. All CMV-PTC patients had excellent response to initial therapy. Conclusions: Because of the association between FAP or colon cancer with multifocal CMV-PTC, we confirm that mutational analysis of the APC gene and colonoscopy should be carried out in these patients when multiple thyroid tumors are found.

Risk of thyroid cancer among Caribbean Hispanic patients with familial adenomatous polyposis.

Familial adenomatous polyposis (FAP) is an inherited form of colorectal cancer characterized by hundreds of adenomatous polyps in the colon and rectum. FAP is also associated with thyroid cancer (TC), but the lifetime risk is still unclear. This study reports the standardized incidence ratio (SIR) of TC in Hispanic FAP patients. TC incidence rates in patients with FAP between the periods of January 1, 2006 to December 31, 2013 were compared with the general population through direct database linkage from the Puerto Rico Central Cancer Registry (PRCCR) and the Puerto Rico Familial Colorectal Cancer Registry (PURIFICAR). The study population consisted of 51 Hispanic patients with FAP and 3239 with TC from the general population. The SIR was calculated using the Indirect Method, defined as observed TC incidence among patients with FAP in PURIFICAR's cohort (2006-2013) divided by the expected TC incidence based on the PR population rates (2006-2010). SIR values were estimated by sex (male, female, and overall). This study received IRB approval (protocol #A2210207). In Hispanic patients with FAP, the SIR (95% CI) for TC was 251.73 (51.91-735.65), with higher risk for females 461.18 (55.85-1665.94) than males 131.91 (3.34-734.95). Hispanic FAP patients are at a high risk for TC compared to the general population. Our incidence rates are higher than previous studies, suggesting that this community may be at a higher risk for TC than previously assumed. Implementation of clinical surveillance guidelines and regular ultrasound neck screening in Hispanic FAP patients is recommended.