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Epstein-Barr virus (EBV) can rarely induce smooth muscle tumors (SMTs). A 20-year-old female patient underwent kidney transplantation for renal failure. Since then, she has been treated with immunosuppressants, including a calcineurin inhibitor, tacrolimus, and prednisolone, owing to the immunological rejection. Three years later, she developed large liver tumors (diameter >5 cm) and multiple small lung tumors that were identified as EBV-SMTs based on the results of liver biopsy/histopathology. No intervention was performed except for the addition of a mammalian target of the rapamycin inhibitor, everolimus, which inhibits both immune reaction and SMT growth. Finally, after 8 years, the transplanted kidney became nonfunctional, and immunosuppressant administration became unnecessary as urinary dialysis was started. Under these circumstances, SMT growth was observed despite the absence of immunosuppressant administration. Three months after the cessation of the immunosuppressants, EBV-SMTs in the liver and lungs shrank slightly. To the best of our knowledge, this is the first report on the genomic profile of this rare tumor. The clinical course of our patient indicates that EBV can induce SMTs, and immunological suppression of EBV may inhibit the activity of these tumors., Competing Interests: The authors have no conflicts of interest to declare., (© 2023 The Author(s). Published by S. Karger AG, Basel.)

Intimal sarcoma is an extremely rare mesenchymal tumor arising in the great vessels. To date, intimal sarcoma has not been reported in patients with Lynch syndrome (LS), even though this syndrome lacks DNA mismatch repair ability genetically and is prone to various malignancies. This patient was diagnosed with LS by the Revised Amsterdam Criteria II, and she suffered from intimal sarcoma in the left pulmonary artery. She had a germline missense variant of PMS2 (c.1399G>A, pV467I) which is classified as a variant of unknown significance. In her intimal sarcoma, PMS2 expression was decreased. Additionally, it exhibited microsatellite instability and a high tumor mutational burden (69 mutations/Mb) which are features of mismatch repair deficiency, although PMS2 (c.1399G>A, pV467I) missense is a variant of unknown significance. The metastatic lesions of intimal sarcoma in this patient responded heterogeneously to pembrolizumab, an immune checkpoint inhibitor. Cytotoxic agents and radiation were also effective for some metastatic lesions, but some lesions, including her liver metastases, were resistant. The hypermutable nature of the LS genotype might acquire resistance to an immune checkpoint inhibitor and other cytotoxic agents such as occurred with her liver metastases., Competing Interests: The authors have no conflicts of interest to declare., (© 2023 The Author(s). Published by S. Karger AG, Basel.)

Cancer of unknown primary (CUP) accounts for 5% of all malignancies. Patients with CUP may live averagely for 8 months after diagnosis, and thus, rapid and reasonable diagnosis is necessary. Among patients with CUP, anaplastic lymphoma kinase (ALK)-overexpressing CUPs, whose primary sites were confirmed to be the lungs (Lung-CUP) by using antibodies against cytokeratin 7, thyroid transcription factor-1, and Napsin A, along with clinical characteristics progressed rapidly and were very sensitive to the ALK inhibitor alectinib. The incidence of ALK alteration in Lung-CUP is 19%. Consequently, it is advised that Lung-CUP be examined by immunohistochemistry (IHC) with an anti-ALK antibody. Alternative examinations, such as a cancer genome test, require as much as 2 months to complete, whereas IHC can be completed within days. In this report, a rapid assessment by IHC led to alectinib treatment, which resulted in good outcomes in 2 cases of Lung-CUP. Alectinib was effective for ALK-altered Lung-CUPs., Competing Interests: The authors have no conflict of interest relevant to this report to declare., (Copyright © 2022 by S. Karger AG, Basel.)