Epstein–Barr virus-associated smooth muscle tumors (EBV-SMTs) are rare soft tissue neoplasms that typically occur in conditions of secondary immunodeficiency due to human immunodeficiency virus or immunosuppression after organ transplantation. Beyond that, EBV-SMTs occur in patients with primary immunodeficiencies (PIDs). EBV-SMTs pathogenesis is still unclear but it was shown that the key mechanism of the tumor development is T- and NK-cell defect. Treatment strategy depends not only on tumor localization and resectability, but also on immunodeficiency etiology and its correction possibility. Here we report literature review and two patients with combined PIDs (CARMIL2- and ATM-genes deficiency) who developed EBV-SMT. In each case, the parents gave consent to the use of their child's data, including photographs, for research purposes and in publications.