Primary central nervous system (CNS) extranodal NK/T-cell lymphoma, nasal type (NKTCL), is an extremely rare tumor. To the best of our knowledge, only four cases have been described previously. Here, we report a case of primary CNS NKTCL in a 25-year-old immunocompetent Chinese male. The patient presented with worsening dizziness, headaches, and vomiting for approximately 2 weeks. Magnetic resonance imaging demonstrated three masses with solid components entirely in the parenchyma of the right hemisphere, and no sinonasal/nasopharyngeal lesions were found. The patient underwent a partial resection of the right temporal mass. Histological examination revealed that intermediate-sized, pleomorphic lymphocytes were arranged in an angiocentric distribution with large geographic necroses. The tumor cells expressed CD3ε, CD56, TIA-1, granzyme B, and Epstein-Barr virus-encoded RNAs. A rearrangement study showed T-cell receptor γ-chain gene rearrangement with monoclonal appearance. Postoperative chemotherapy and radiotherapy were also given, but the lymphoma failed to respond to therapy and the patient died 18 months later. Our observation and the four others found in the literature indicate that primary CNS NKTCL occurs predominantly in adult males. This is the youngest patient with primary CNS NKTCL reported.

Abstract. Thymidine kinase 1 (Tk1) is an enzyme involved in the synthesis of dna precursors. in studies using immunohistochemistry, it was reported to be a more useful proliferation marker than ki-67 and Pcna in breast, lung and colorectal carcinoma. in this study, we extend the work of prior breast carcinoma studies by investigating the expression of Tk1 in 132 patients with usual ductal hyperplasia (udH), atypical ductal hyperplasia (adH), ductal carcinoma in situ (dciS) and invasive ductal carcinoma (idc). Tk1 and ki-67 expression were determined with monoclonal antibodies using the SP technique. The expression of TK1 was found to be significantly increased in the breast ductal carcinomas in the following manner: udH

Leydig cell tumour (LCT) is an uncommon tumour that typically occurs in the testis. Primary epididymal LCT is extremely rare. To the best of our knowledge, only two cases have been reported in the world literature. Herein, we report a case of primary epididymal LCT in a 41-year-old Chinese male. The patient presented with right epididymal swelling for 3 months without endocrine manifestations, including gynaecomastia and decreased libido. Scrotal ultrasound demonstrated a mass about 1.5 cm in diameter entirely in the cephalic region of right epididymis. No abnormality was found in his bilateral testes. The patient underwent total mass resection without post-operative therapy. Histological examination revealed that the well-circumscribed tumour was separated by conspicuous hyalinised fibrous stroma; the tumour cells were large and polygonal with round nuclei and abundant eosinophilic cytoplasm. Immunophenotypically, the tumour cells expressed four markers of sex cord differentiation (calretinin, melanA, CD99 and inhibin). There was no recurrence at 2-year follow-up. Our observation once again confirms that LCT could primarily occur in the epididymis, and we suppose that it probably originates from the ectopic Leydig cells. As little is known about the pathogenesis and prognosis for such a rare disease, accumulation of more pathological and clinical data can help to better interpret this tumour.

The M129V mutation in the human prion protein gene (PRNP) is the primary site linked to susceptibility to prion diseases in humans. The heterozygous state of this allele has been proven to be more resistant to prion-related diseases such as Creutzfeldt-Jakob disease.