Anal Squamous Cell Carcinoma in a Patient with Myasthenia Gravis: Is Immunosuppression the Main Underlying Etiology?

Patients who are immunocompromised by diseases such as human immunodeficiency virus (HIV) infection are more prone to develop some malignancies such as Kaposi's sarcoma and central nervous system (CNS) lymphomas. Historically, anal squamous cell carcinoma (SCC) was also included on the list as an acquired immunodeficiency syndrome (AIDs)-defining cancer. Similarly, compromised immune disorders including severe immunosuppression, haematologic malignancies, and solid organ transplantation have been identified as important risk factors for the development of anal SCC. Review of the medical literature showed only sporadic cases of anal SCC in patients with pre-existing myasthenia gravis (MG), with or without thymoma. We present here a case of anal SCC in a patient with several years history of MG who was receiving intravenous immunoglobulin (IVIG). We believe this association is explained by the autoimmune nature of the disease and the use of immunosuppressive medications to treat it. To further support our case, we also present a review of the literature associating anal SCC with MG.