Novel genetic mutation in the background of Carney complex

Whole genome sequencing resolves 10 years diagnostic odyssey in familiar myxoma

Carney complex (CNC) is an ultrarare disorder causing cutaneous and cardiac myxomas, primary pigmented nodular adrenocortical disease, hypophyseal adenoma, and gonadal tumours. Genetic alterations are often missed under routine genetic testing. Pathogenic variants in PRKAR1A are identified in most cases, while large exonic or chromosomal deletions have only been reported in a few cases. Our aim was to identify the causal genetic alteration in our kindred with a clinical diagnosis of CNC and prove its pathogenic role by functional investigation. Targeted testing of PRKAR1A gene, whole exome and whole genome sequencing (WGS) were performed in the proband, one clinically affected and one unaffected relative. WGS identified a novel, large, 10,662 bp (10.6 kbp; LRG_514t1:c.-10403_-7 + 265del; hg19, chr17:g.66498293_66508954del) deletion in the promoter of PRKAR1A in heterozygous form in the affected family members. The exact breakpoints and the increased enzyme activity in deletion carriers compared to wild type carrier were proved. Segregation analysis and functional evaluation of PKA activity confirmed the pathogenic role of this alteration. A novel deletion upstream of the PRKAR1A gene was proved to be the cause of CNC. Our study underlines the need for WGS in molecular genetic testing of patients with monogenic disorders where conventional genetic analysis fails.

Overview of the 2022 WHO Classification of Familial Endocrine Tumor Syndromes

This review of the familial tumor syndromes involving the endocrine organs is focused on discussing the main updates on the upcoming fifth edition of the WHO Classification of Endocrine and Neuroendocrine Tumors. This review emphasizes updates on histopathological and molecular genetics aspects of the most important syndromes involving the endocrine organs. We describe the newly defined Familial Cancer Syndromes as MAFA-related, MEN4, and MEN5 as well as the newly reported pathological findings in DICER1 syndrome. We also describe the updates done at the new WHO on the syndromic and non-syndromic familial thyroid diseases. We emphasize the problem of diagnostic criteria, mention the new genes that are possibly involved in this group, and at the same time, touching upon the role of some immunohistochemical studies that could support the diagnosis of some of these conditions. As pathologists play an important role in identifying tumors within a familial cancer syndrome, we highlight the most important clues for raising the suspicious of a syndrome. Finally, we highlight the challenges in defining these entities as well as determining their clinical outcome in comparison with sporadic tumors. Instead of the usual subject review, we present the highlights of the updates on familial cancer syndromes by answering select questions relevant to practicing pathologists.

Inherited Follicular Epithelial-Derived Thyroid Carcinomas: From Molecular Biology to Histological Correlates

Cancer derived from thyroid follicular epithelial cells is common; it represents the most common endocrine malignancy. The molecular features of sporadic tumors have been clarified in the past decade. However the incidence of familial disease has not been emphasized and is often overlooked in routine practice. A careful clinical documentation of family history or familial syndromes that can be associated with thyroid disease can help identify germline susceptibility-driven thyroid neoplasia. In this review, we summarize a large body of information about both syndromic and non-syndromic familial thyroid carcinomas. A significant number of patients with inherited non-medullary thyroid carcinomas manifest disease that appears to be sporadic disease even in some syndromic cases. The cytomorphology of the tumor(s), molecular immunohistochemistry, the findings in the non-tumorous thyroid parenchyma and other associated lesions may provide insight into the underlying syndromic disorder. However, the increasing evidence of familial predisposition to non-syndromic thyroid cancers is raising questions about the importance of genetics and epigenetics. What appears to be "sporadic" is becoming less often truly so and more often an opportunity to identify and understand novel genetic variants that underlie tumorigenesis. Pathologists must be aware of the unusual morphologic features that should prompt germline screening. Therefore, recognition of harbingers of specific germline susceptibility syndromes can assist in providing information to facilitate early detection to prevent aggressive disease.

The Spectrum of Thyroid Gland Pathology in Carney Complex: The Importance of Follicular Carcinoma

The initial description of Carney complex (CNC) in 1985 included myxomas, spotty skin pigmentation, and endocrine overactivity (of the adrenal, the pituitary, and the testis). In 1997, thyroid neoplasms were found in 3 patients with CNC and involvement of the gland in the syndrome was apparent. Herein, we describe the clinical, pathologic, and follow-up findings in 26 patients with CNC and a disorder of the thyroid gland. The patients were predominantly middle-aged women with an asymptomatic thyroid mass. Four patients had hyperthyroidism, which was caused by follicular hyperplasia in 2 patients and by toxic adenoma in 2 others. Pathologic findings included benign lesions (follicular hyperplasia, nodular hyperplasia, and follicular adenoma) in 16 patients and carcinomas (follicular or papillary) in 10 patients. The follicular carcinomas had unusual features, multifocality, bilaterality, and lymph node metastasis. The tumor was fatal in 3 of 4 patients with a tumor ≥3 cm in diameter. One patient had an unusual multifocal microscopic follicular hyperplasia. Detection and treatment of the thyroid neoplasms in patients with CNC requires long-term follow-up of patients with the syndrome.

[Leydig cell, Sertoli cell and adult granulosa cell tumors]

According to the World Health Organization (WHO) classification Leydig cell tumors, Sertoli cell tumors and granulosa cell tumors of the testes belong to the group of sex cord-stromal tumors. These tumors most frequently occur sporadically but in rare cases can be associated with syndromes. These tumor entities show characteristic morphological changes, which in combination with specific immunohistochemical markers facilitate the diagnosis. Recent results of molecular pathological investigations, especially beta-catenin mutation analysis, allow a better categorization of these tumor entities.

Case studies of two related Chinese patients with Carney complex presenting with extensive cardiac myxomas and PRKAR1A gene mutation of c.491_492delTG

Carney complex is an autosomal dominant disease that is clinically characterized by cardiac myxomas, spotty skin pigmentation, and endocrine overactivity. Carney complex is most commonly caused by mutations in the PRKAR1A gene on chromosome 17q22-24. Currently, there are at least 117 pathogenic mutations in PRKAR1A that have been identified. Herein, we report on two cases of Carney complex in related Chinese patients with a c.491_492delTG mutation that presented with multiple and extensive cardiac myxomas and skin pigmentation.

[Sex cord gonadal stromal tumors]

According to the World Health Organization (WHO) classification from 2004, sex cord gonadal stromal tumors are divided into Leydig cell tumors, Sertoli cell tumors, granulosa cell tumors, tumors of the thecoma-fibroma group, incompletely differentiated sex cord gonadal stromal tumors, mixed forms of sex cord gonadal stromal tumors and tumors containing both germ cell and sex cord gonadal stromal elements. These tumors can appear sporadically or in combination with hereditary syndromes. To diagnose these rare tumors the combination of characteristic morphological aspects and various immunohistochemical markers is useful. Latest investigations demonstrate the potential role of mutation analyses in the diagnosis of this heterogeneous group of tumors.