Diagnosis and treatment of primary seminoma of the prostate: A case report and review of literature.

BACKGROUND: Primary seminoma of the prostate (PSP) is a rare type of extragonadal germ cell tumour that is easily misdiagnosed, owing to the lack of specific clinical features. It is therefore necessary for clinicians to work toward improving the accuracy of PSP diagnosis. CASE SUMMARY: A 59-year-old male patient presenting with acute urinary retention was admitted to a local hospital. A misdiagnosis of benign prostatic hyperplasia led to an improper prostatectomy. Histopathology revealed PSP invading the bladder neck and bilateral seminal vesicles. Further radiotherapy treatment for the local lesion was performed, and the patient had a disease-free survival period of 96 mo. This case was analysed along with 13 other cases of PSP identified from the literature. Only four of the cases (28.6%) were initially confirmed by prostate biopsy. In these cases, imaging examinations showed an enlarged prostate (range 6-11 cm) involving the bladder neck (13/14). Of the 14 total cases, 11 (78.6%) presented typical pure seminoma cell features, staining strongly positive for placental alkaline phosphatase, CD117, and OCT4. The median age at diagnosis was 51 (range 27-59) years, and patients had a median progression-free survival time of 48 (range 6-156) mo after treatment by cisplatin-based chemotherapy combined with surgery or radiotherapy. The remaining three were cases of mixed embryonal tumours with focal seminoma, which had clinical features similar to those of pure PSP, in addition that they also had elevated serum alpha-fetoprotein, beta-human chorionic gonadotropin, and lactose dehydrogenase. CONCLUSION: PSP should be considered in patients younger than 60 years with an enlarged prostate invading the bladder neck. Further prostate biopsies may aid in proper PSP diagnosis. Cisplatin-based chemotherapy is still the main primary therapy for PSP.

Elevated basal serum levels of calcitonin and simultaneous surgery of MEN2A-specific tumors.

Multiple endocrine neoplasia type 2A (MEN2A) is a rare syndrome caused almost by germline RET mutation, and characterized by medullary thyroid carcinoma (MTC), in combination or not with pheochromocytoma (PHEO), hyperparathyroidism (HPTH), cutaneous lichen amyloidosis (CLA), and Hirschsprung's disease (HD). The basal serum calcitonin (Ctn)/carcinoembryonic antigen (CEA) levels are significantly correlated with the MTC stage. Metachronous surgery of MEN2A-specific tumors is a routine procedure. We aimed to explore the clinical significance of pro-gastrin-releasing peptide (proGRP) in MTC with elevated Ctn and simultaneous surgery of MEN2A-specific tumors. We retrospectively investigated 8 RET mutation carriers of 2 Chinese pedigrees with MEN2A. Clinical profiles, imaging examinations, preoperative and postoperative biochemical data, surgical procedures, and follow-up records were evaluated. Three patients showed levels of elevated Ctn but normal proGRP. Among them, one patient (FAIII-6) in Family A (one for RET C634R mutation), diagnosed with bilateral MTC, left PHEO, bilateral HPTH, and CLA, classified as MEN2A-related CLA subtype, underwent successfully simultaneous adrenal-sparing surgery (ASS), total thyroidectomy (TT), and parathyroidectomy, while TT of the other two patients (FBII-3 and FBIII-7) diagnosed with bilateral MTC in Family B (all for RET C618R mutation) were performed. Unexpectedly, the absence of neck lymph node MTC metastasis was indicated by histopathological examination. Postoperatively, all had consistently "undetectable" or normal levels of Ctn/CEA during follow-up. Patients with normal proGRP, despite high levels of Ctn, might have no regional lymph node MTC metastasis, and neck dissection should be avoided. Moreover, simultaneous surgery for coexistent PHEO and either MTC or HPTH is an approach of choice to use as an alternative treatment pattern. Recognition of MEN2A-related CLA and subsequently early screening of RET mutation may be favorable for timely management of MEN2A-specific tumors.

Spectrum of Germline RET variants identified by targeted sequencing and associated Multiple Endocrine Neoplasia type 2 susceptibility in China.

BACKGROUND: Germline RET mutations and variants are involved in development of multiple endocrine neoplasia type 2 (MEN2). The present study investigated a spectrum of RET variants, analyzed genotype-phenotype relationships, and evaluated their effect on the MEN2 phenotype in Han Chinese patients. METHODS: Targeted sequencing detected germline RET variants in 697 individuals, including 245 MEN2, 120 sporadic medullary thyroid cancer (MTC), and 15 pheochromocytoma (PHEO) patients and their 493 relatives. In silico analyses and classifications following ACMG-2015 were performed. Demographic, clinical variant types, and endocrine neoplasia molecular diagnosis records were also analyzed. RESULTS: Nineteen different RET mutations (18 point and 1 del/ins mutations) in 214 patients with MEN2A (97.7%) or MEN2B (2.3%) were found, of which exon 11/10 mutations accounted for 79% (169/214). Nineteen compound mutations were found in 31 patients with MEN2A. Twenty-three variants (18 single and 5 double base substitution/compound variants) non-classification were also found. Of these, 17 (3 of pathogenic, 10 of uncertain significance, 2 of likely benign and 2 as benign) were found in 31 patients with MTC/PHEO. The remaining 6 variants (4 of uncertain significance and 2 of likely benign) found in 8 carriers had no evidence of MEN2. The entire cohort showed MEN2A-related PHEO, all occurring in exons 11/10, particularly at C634. Kaplan-Meier curves showed age-dependent penetration rates of MTC and PHEO, and occurrence rates of PHEO in patients with exon 11 mutations were all higher than those within exon 10; these bilateral PHEO were always associated with exon 11 mutations (all P < 0.05). While patient offspring had PHEO, parents with MEN2A had none, the frequency was approximately 10%. Interestingly, at least 6.8% of families were adoptive. Also, 3 non-hotspot RET variants (R114H, T278N, and D489N) appeared with high frequency. Conversely, polymorphism S836S was absent. CONCLUSIONS: These data are largely consistent with current evidence-based recommendations in the clinical practice guidelines. Diversity of RET variants or carriers may involve a different natural disease course. Further large-scale targeted sequencing studies will serve as an accurate and cost-effective approach to investigating MEN2 genotype-phenotype correlations for discovery of rare or unknown variants of RET.

Multiple Endocrine Neoplasia Type 2B Associated Mixed Medullary and Follicular Thyroid Carcinoma in A Chinese Patient with RET M918T Germline Mutation.

BACKGROUND: Mixed medullary and follicular thyroid carcinoma (MMFC) displays heterogeneous morphological components and immunophenotypical features intermingled within the same lesion, which is rare and most described in the sporadic form. We report herein a Chinese patient with multiple endocrine neoplasia type 2B (MEN2B) harboring germline RET M918T and associated MMFC. METHODS: A case of a 39-year-old male patient with MEN2B presented palpable neck masses in both thyroid lobes (maximum sizes: left, 3.9 cm; right, 5.4 cm) and a definitive phenotype. Serum levels of calcitonin (Ctn; >2000pg/mL), carcinoembryonic antigen (CEA; 719.27ng/mL), and thyroglobulin (Tg; 98.54ng/mL) were high. Fine-needle aspiration cytology showed features positive for malignancy, suggesting the possibility of medullary thyroid carcinoma (MTC). Total thyroidectomy, along with extending bilateral neck lymph nodes dissection, and subsequently, genetics family screening were performed. RESULTS: The histopathological examination yielded a diagnosis of MMFC that showed immunohistochemical characteristic patterns of the component of MTC positive for Ctn and CEA, chromogranin A, and the follicular carcinoma components were positive for Tg. Lymph node metastasis was observed showing medullary tumoral cells positive for Ctn and follicular-like structures lacking tumor cells positive for Tg staining (T4bN1bM0). Genetics screening confirmed RET M918T (c.2753T>C) mutation manifested in the patient but was not detected in other family members. Follow up showed that the serum Ctn, CEA and Tg levels respectively dropped to 54.38pg/ml, 4.16ng/mL and 0.04ng/mL 16 months after the surgery. CONCLUSION: Particular and diverse patterns of MMFC should be recognized with immunostaining features. MMFC occurring in a patient with MEN2B harboring RET M918T may be unique biological behavior and the treatment is mostly radical surgery.

RET S409Y Germline Mutation and Associated Medullary Thyroid Carcinoma.

Background: Inherited medullary thyroid carcinoma (MTC) is primarily caused by RET mutations that are commonly localized in exons 5, 8, 10, 11, and 13-16. In this study, we report pedigrees for individuals with MTC that harbor a germline S409Y variant within exon 6 of the RET proto-oncogene. Methods: Targeted sequencing was used to diagnose four apparently sporadic MTC index cases carrying the germline RET S409Y (c.1226 C>A) variant. Subsequently, 27 relatives of these individuals underwent clinical and genetic assessments and/or thyroid surgery. Furthermore, in silico analyses and in vitro assays were performed to predict or verify the potential oncogenic activity of the S409Y variant. Results: Overall, 15 of 31 participants were found to carry the RET S409Y variant. Of these, 6 presented with isolated MTC (mean age 50.2 years; range 41-75 years), of which 3 presented with neck lymph node metastases and 2 presented with distant liver or lung metastases. Among the remaining 9 carriers, 3 (mean age 56 years; range 41-76 years) had elevated serum calcium-stimulated calcitonin (sCtn) or concurrent marginally elevated serum calcitonin (Ctn) levels, whereas the other 6 (mean age 37.5 years; range 14-52 years) exhibited typical Ctn/sCtn levels (p < 0.05). None of the 15 carriers in these 4 families presented clinical evidence of pheochromocytoma, hyperparathyroidism, or Hirschsprung's disease. In silico analyses revealed that S409Y was a "possibly damaging" mutation that could affect the RET protein inter-domain interface. An in vitro assay revealed that the phosphorylation level of RET tyrosine 905 was relatively higher in the RET S409Y mutant than in wild-type (WT) RET. Moreover, transfection of HEK 293 cells with S409Y enhanced the phosphorylation activity of AKT, ERK pathways, and it increased cell proliferation compared with WT RET, but to a lesser degree than that for the RET C618Y and C634Y mutations. Conclusions: This study demonstrates that the novel germline RET S409Y variant is likely pathogenic and is associated with lower penetrance of MTC than that for the C618Y and C634Y mutations. Individuals with S409Y should be managed using a personalized approach, and additionally, "at-risk" family members should be evaluated. Additional studies are needed to elucidate the correlation between the S409Y mutation and multiple endocrine neoplasia type 2-specific tumors.

The Clinical Spectrum of Multiple Endocrine Neoplasia Type 2A with Cutaneous Lichen Amyloidosis in Ethnic Han Chinese.

This study systematically reviewed previous literatures and analyzed the genotype-phenotype relationship between the multiple endocrine neoplasia type 2A (MEN 2A)-cutaneous lichen amyloidosis (CLA) and RET/OSMR/IL31RA mutations. RET/OSMR/IL31RA screening was performed on 8 RET-carriers from 3 independent Chinese MEN 2A families. Besides, 51 MEN 2A-CLA patients in 116 RET carriers from literatures were clustered and analyzed. Our results indicated that almost all MEN 2A-CLA patients exhibited CLA which was located in the scapular region and carried RET mutation at codon 634. Meanwhile, we firstly described MEN 2A-CLA here in Chinese Han patient with RET p.C634F mutation.

Genetic diagnosis of a Chinese multiple endocrine neoplasia type 2A family through whole genome sequencing.

Approximately 98% of patients with multiple endocrine neoplasia type 2A (MEN 2A) have an identifiable RET mutation. Prophylactic or early total thyroidectomy or pheochromocytoma/parathyroid removal in patients can be preventative or curative and has become standard management. The general strategy for RET screening on family members at risk is to sequence the most commonly affected exons and, if negative, to extend sequencing to additional exons. However, different families with MEN 2A due to the same RET mutation often have significant variability in the clinical exhibition of disease and aggressiveness of the MTC, which implies additional genetic loci exsit beyond RET coding region. Whole genome sequencing (WGS) greatly expands the breadth of screening from genes associated with a particular disease to the whole genome and, potentially, all the information that the genome contains about diseases or traits. This is presumably due to additive effect of disease modifying factors. In this study, we performed WGS on a typical Chinese MEN 2A proband and identified the pathogenic RET p.C634R mutation. We also identified several neutral variants within RET and pheochromocytoma-related genes. Moreover, we found several interesting structural variants including genetic deletions (RSPO1, OVCH2 and AP3S1, etc.) and fusion transcripts (FSIP1-BAZ2A, etc.).