Iatrogenic solid tumors following immunosuppressive therapy.

Immunosuppression induced by chronic medication, such as occurs post-transplantation, may increase a patient's risk of developing solid tumors. These are often rare tumors characterized by odd presentations. This review focuses on commonly encountered iatrogenic, non-hematopoietic solid tumors following immunotherapy and provides a practical approach to their diagnosis. All of the malignancies covered in this review are viral-induced. They include human papillomavirus (HPV)-associated carcinomas, Epstein-Barr virus (EBV)-associated tumors, Merkel cell polyomavirus (MCPyV)-related Merkel cell carcinoma, and Human Herpesvirus 8 (HHV8)-related Kaposi sarcoma. The complementary diagnostic role of ancillary studies, such as immunohistochemistry and in-situ hybridization that target these oncogenic viruses, is addressed.