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We report a case of adult T‐cell leukemia/lymphoma (ATLL) with angioimmunoblastic T‐cell lymphoma (AITL/nTFHL‐AI)‐like feature. An 88‐year‐old Japanese woman with seropositive for the Human T‐lymphotropic virus type 1 (HTLV‐1) was incidentally diagnosed with generalized lymphadenopathy. Biopsy of the cervical lymph node demonstrated the proliferation of small‐ or medium‐sized and large atypical lymphocytes associated with eosinophils, high endothelial venules, and clear cells. Immunohistochemical analysis revealed atypical lymphocytes were CD3‐ and CD4‐positive. Atypical T cells bore the T‐follicular helper phenotype (PD1, ICOS, and BCL6) and were positive for CD25 and chemokine receptor 4. Epstein‐Barr virus encoded RNA‐positive cells were scattered in the background via in situ hybridization. The histological findings were similar to those of AITL/nTFHL‐AI; however, the immunohistochemical results did not exclude the possibility of ATLL. Southern blot analysis detected integration of HTLV‐1 proviral DNA. The RHOA Gly 17 Val (G17V) mutation was detected by the peptide nucleic acid‐locked nucleic acid clamp method. Finally, the patient was diagnosed with ATLL with AITL‐like feature and exhibited a similar morphology, immunophenotype, and mutational signature to AITL/nTFHL‐AI. ATLL mimics other types of T‐cell lymphomas. Thus, in HTLV‐1 endemic areas, routine screening for HTLV‐1 serology is necessary to avoid misdiagnosis of other lymphoid malignancies. [ABSTRACT FROM AUTHOR]

Background. Micronodular thymic carcinoma (MTC) with lymphoid hyperplasia is believed to be the malignant counterpart of micronodular thymoma (MT) with lymphoid hyperplasia. Since MT and MTC share a similar morphology, MTC is considered a malignant form of MT; there have been a few malignant transformations from MT to MTC. We report a case of MTC with lymphoid hyperplasia. Case presentation. A 53-year-old woman presented with an incidental tumor on a chest X-ray. The resected tumor consisted of nodular epithelial nests and lymphoid tissue within a surrounding germinal center. Some epithelial nests showed apparent malignant morphology. Atypical epithelial cells with large vesicular nuclei formed nests, some of which showed comedo necrosis. These cells showed transition continuously to low-grade type B thymoma-like cells, demonstrating cord-like arrangements. Carcinomatous elements, expressed GLUT1, CD5, KIT, and BCL2; conversely, low-grade nests displayed attenuated expression of these markers. GTF2I point mutation and Langerhans/dendritic cells, which are indicators of favorable thymoma prognosis, were not detected. Due to pleural metastasis, the patient was treated with lenvatinib 27 months postoperatively. Conclusions. This is the first report of a partially low-grade, GTF2I -negative MTC. Histological and genetic findings might be predictive of tumor prognosis. [ABSTRACT FROM AUTHOR]

Simple Summary: We describe the currently known histopathological aspects of the prognostic factors for salivary gland cancers and discuss the genetics or molecules used as diagnostic tools that might serve as treatment targets in the future. Salivary gland cancers (SGCs) are diagnosed using histopathological examination, which significantly contributes to their progression, including lymph node/distant metastasis or local recurrence. In the current World Health Organization (WHO) Classification of Head and Neck Tumors: Salivary Glands (5th edition), malignant and benign epithelial tumors are classified into 21 and 15 tumor types, respectively. All malignant tumors have the potential for lymph node/distant metastasis or local recurrence. In particular, mucoepidermoid carcinoma (MEC), adenoid cystic carcinoma (AdCC), salivary duct carcinoma, salivary carcinoma, not otherwise specified (NOS, formerly known as adenocarcinoma, NOS), myoepithelial carcinoma, epithelial–myoepithelial carcinoma, and carcinoma ex pleomorphic adenoma (PA) are relatively prevalent. High-grade transformation is an important aspect of tumor progression in SGCs. MEC, AdCC, salivary carcinoma, and NOS have a distinct grading system; however, a universal histological grading system for SGCs has not yet been recommended. Conversely, PA is considered benign; nonetheless, it should be cautiously treated to avoid the development of metastasizing/recurrent PA. The aim of this review is to describe the current histopathological aspects of the prognostic factors for SGCs and discuss the genes or molecules used as diagnostic tools that might have treatment target potential in the future. [ABSTRACT FROM AUTHOR]