Papillary carcinoma occurring within an adenomatous goiter of the thyroid gland in Cowden's disease

Occurrence and Natural History of Thyroid Cancer in Patients with Cowden Syndrome

INTRODUCTION

Cowden syndrome patients are at an increased risk of developing differentiated thyroid carcinoma (DTC). There are limited studies of thyroid cancer biology within this population. We aimed to describe the frequency and progression of DTC in this population.

METHOD

We reviewed all patients with clinically or genetically confirmed Cowden syndrome treated at our institution between 1979 and 2017. Presentation, operative details, pathology, and adjuvant treatment for all thyroid diseases were analyzed.

RESULTS

Forty-seven patients were identified. Thirty-seven received a clinical diagnosis while 10 tested positive on genetic testing for the PTEN gene. Average follow-up time was 10 years. Twenty-three patients underwent a total thyroidectomy. Nine patients were diagnosed with thyroid cancer, with a mean age of 28.5 years, 4 cases of the follicular variant of papillary thyroid cancer (PTC), 4 of PTC, and 1 of cystic PTC. One patient required an interval lateral neck dissection but no patients developed distant metastasis. Fourteen patients underwent thyroidectomy, 12 due to follicular adenoma, Hürthle cell adenoma, or multinodular goiter, 1 due to Graves' disease, and 1 who elected to undergo a prophylactic thyroidectomy. No mortality was associated with thyroid cancer in these patients.

CONCLUSION

Patients with Cowden syndrome are at a significantly increased risk of developing DTC and have a younger age of onset. In this study, 20% of the patients with Cowden syndrome were diagnosed with DTC, but distant metastasis and overall mortality were absent. Clinical features were similar to those of sporadic DTC, proving that, apart from screening, Cowden syndrome-related DTC can be treated in similar fashion.

Thyroid pathology in PTEN-hamartoma tumor syndrome: characteristic findings of a distinct entity

BACKGROUND

Phosphatase and tensin homolog deleted on chromosome ten (PTEN)-hamartoma tumor syndrome (PHTS) is a complex disorder caused by germline inactivating mutations of the PTEN tumor suppressor gene. PHTS includes Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS), and Proteus-like syndromes. Affected individuals develop both benign and malignant tumors in a variety of tissues, including the thyroid. This study is to better characterize and describe the thyroid pathology within the different entities of this syndrome, and examine whether there is an association between specific thyroid findings and different PTEN mutations.

METHODS

Twenty patients with known PTEN mutations, and/or clinical diagnosis of PHTS, and thyroid pathology were identified: 14 with CS and 6 with BRRS.

RESULTS

Thyroid pathology findings were as follows: multiple adenomatous nodules in a background of lymphocytic thyroiditis (LT) in 75%, papillary carcinoma in 60%, LT alone in 55%, follicular carcinoma in 45%, C-cell hyperplasia in 55%, and follicular adenomas in 25%. Within the papillary carcinoma group, there were 6 microcarcinomas, 5 follicular variants, and 1 classical type.

CONCLUSIONS

There were no morphologic differences between the thyroid findings in CS and BRRS. Also, there was no correlation between specific PTEN germline mutations (exons 5, 6, and 8) and pathologic findings. Distinctive and characteristic findings in PHTS include multiple unique adenomatous nodules in a background of LT, and C-cell hyperplasia; it is vital that pathologists recognize the classical histologic features of this syndrome to alert clinicians to the possibility of this syndrome in their patients.

Thyroid cancer of follicular cell origin in inherited tumor syndromes

Well-differentiated thyroid cancer accounts for 95% of thyroid malignancies. In contrast to medullary thyroid carcinoma, in which about 25% are familial, only 5% of follicular cell-derived thyroid carcinomas are a component of a familial cancer syndrome. The familial follicular cell-derived tumors or nonmedullary thyroid carcinoma encompass a heterogeneous group of diseases, and are classified into 2 distinct groups: syndromic-associated tumors, occurring in syndromes in which nonmedullary thyroid carcinomas are the predominant tumor encountered, and nonsyndromic tumors, those occurring in tumor syndromes in which thyroid involvement is a minor component. The first group, syndromic-associated tumors, includes phosphase and tensin (PTEN)-hamartoma tumor syndrome/Cowden syndrome, familial adenomatous polyposis/Gardner syndrome, Carney complex type 1, Werner syndrome, and Pendred syndrome. Other syndromes, as McCune Albright syndrome, Peutz-Jeghers syndrome, and Ataxia-teleangiectasia syndrome may be associated with the development of follicular cell-derived tumors, but the link is less established than the above syndromes. The syndromic-associated tumors are the focus of this review. The second group of familial follicular cell-derived tumors syndromes or nonsyndromic tumors, in which nonmedullary thyroid carcinomas are the major findings, include pure familial papillary thyroid carcinoma, with or without oxyphilia, familial papillary thyroid carcinoma with papillary renal cell carcinoma, and familial papillary thyroid carcinoma with multinodular goiter. This review will discuss the clinical and pathological findings of the patients with familial syndrome-associated tumors: PTEN-hamartoma tumor syndrome/Cowden syndrome, familial adenomatous polyposis syndrome, Carney complex type 1, Werner syndrome, and Pendred syndrome.

[Hereditary thyroid cancer]

Hereditary thyroid carcinomas are present in about 5% of differentiated (DTC) and 25% of medullary thyroid carcinomas (MTC). They are part of a multiorgan tumour syndrome (e. g. FAP Gardner's syndrome with DTC and MEN 2 syndrome with MTC) or confined to the thyroid gland. Hereditary thyroid carcinomas typically show multifocal growth and occur in young patients. Due to germ cell mutations as the underlying cause of disease, partial thyroidectomies that may be justified in early sporadic carcinomas are not indicated in this type of tumours. In the case of hereditary DTC, the genetic basis of the disease has been demonstrated only in syndromatic tumour variants. In most nonsyndromatic cases, specific genetic alterations have not yet been identified. In both types of hereditary DTC, prophylactic thyroidectomy is not warranted due to the favourable prognosis of tumours that do not differ from sporadic ones. Point mutations of the RET proto-oncogene have been known for 15 years to be the genetic basis of hereditary MTC. Recently several new mutations were discovered; however, final conclusions regarding their clinical significance are not possible at present. Basically it has been shown that the clinical aggressivity of tumour development follows a genotype-phenotype correlation (risk groups 1-3). However, in mutations of all risk classes there exists a wide spectrum of different stages of hereditary C-cell disease in individual risk groups. Regarding time and extent of prophylactic thyroidectomy (without or with lymph node dissection) a combined molecular-biochemical concept including the use of pentagastrin-stimulated calcitonin values is therefore recommended.

Thyroid Medullary Carcinoma in a Teenager With Cowden Syndrome

Cowden syndrome is a multisystemic cancer predisposition disorder, in which the mucocutaneous lesions are the most constant features. We present a case of Cowden syndrome in a teenage boy with hyperkeratotic papules of the facial skin, especially on the eyelids, with episcleritis, proptosis, and papillomatous lesions on the tip of the tongue and lip mucosa. In addition, two nodules in the thyroid gland were detected. On laboratory examination, the carcinoembryonic antigen (CEA) was 34 ng/mL (normal limits: 0-3 ng/mL). Total thyroidectomy was performed. Histopathologic examination of the specimen revealed thyroid medullary carcinoma. After operation, levels of CEA decreased to normal limits.

Cowden disease: a review

Cowden disease is a genetically inherited disorder presenting with multiple hamartomatous and neoplastic lesions in various organs and tissues. We present a review of the diagnostic criteria, clinical presentation, genetics, and management of this condition.

Papillary Thyroid Carcinoma: An Overview

Papillary carcinoma is the most common malignant tumor of the thyroid. It has a variable macroscopic appearance that differs according to the variant microscopic morphologies and the presence or absence of degenerative changes. The histologic variants can be challenging to the pathologist, and some are of clinical significance because of prognostic implications. In this short review, we discuss an approach to papillary carcinoma, the diagnostic dilemmas and controversies, and the ancillary studies that are helpful in resolving them, including immunohistochemistry and molecular studies.

Genetic conditions associated with intestinal juvenile polyps

Juvenile polyps are hamartomatous polyps found primarily in infants and children, and in association with juvenile polyposis (JP; OMIM #174900), Cowden syndrome (CS; OMIM #158350), and Bannayan-Riley-Ruvalcaba syndrome (BRRS; OMIM# 153480). Although solitary juvenile polyps are benign lesions, when present in JP patients they may lead to gastrointestinal cancers. Germline mutations in MADH4 and BMPR1A predispose to JP, and both genes are involved in TGF-beta superfamily signaling pathways. In CS and BRRS, juvenile polyps are a less consistent feature, and CS patients are at risk for breast and thyroid cancers. Mutations of the tumor suppressor gene PTEN have been found in the germline of both CS and BRRS patients. Despite different underlying genetic mechanisms, these and other syndromes share the same phenotypic feature of juvenile polyps.

Abnormal distribution and hyperplasia of thyroid C-cells in PTEN-associated tumor syndromes

INTRODUCTION

Cowden's disease (CD) and Bannayan-Ruvalcaba-Riley syndrome (BRRS) are allelic disorders characterized by multiple hamartomatous overgrowths of the thyroid, breast, skin, and gastrointestinal tract, and an increased risk of developing benign and malignant tumors of the breast and thyroid gland, secondary to germline point mutations in the PTEN gene. In contrast to thyroid epithelial lesions, abnormalities of the C-cells are currently not considered part of the spectrum of manifestations seen in PTEN-associated syndromes.

METHODS

The thyroid glands from two patients with overlapping CD/BRRS phenotypes, and with distinct PTEN mutations, were entirely submitted for histopathological examination, calcitonin immunostaining and C-cell mapping.

RESULTS

Multiple follicular adenomas and adenomatous nodules were present in the thyroid glands from both patients. A microscopic focus of papillary carcinoma was also present in one gland. C-cell hyperplasia was documented in both cases by calcitonin immunostaining.

CONCLUSIONS

PTEN-associated tumor syndromes should be considered in the differential diagnosis of C-cell hyperplasia of the thyroid.