A Rare Coexistence of Turner Syndrome and Mycosis Fungoides: A Case Report

Turner syndrome (TS) is the most common sex chromosome abnormality among females, characterised by short stature, hypergonadotropic hypogonadism, congenital heart anomalies, and an increased risk of autoimmune diseases. Although TS does not typically increase the absolute risk of malignancy, specific cancers, such as those affecting the nervous system and gastrointestinal tract and malignant melanoma, may occur more frequently. Mycosis fungoides (MF) is the most common type of primary cutaneous T-cell lymphoma, typically affecting adults but also seen in children and adolescents. We report an 11.2-year-old girl with TS presenting with substantial weight gain and short stature. Clinical examination revealed characteristic TS features and karyotype analysis confirmed mosaic TS. Following growth hormone (GH) therapy, the patient developed persistent, erythematous, itchy skin lesions diagnosed as CD4+ MF. GH therapy was discontinued, and topical steroids controlled the skin lesions effectively. MF in TS is rare and unexpected, especially in a child. The coexistence of these conditions suggests a potential link between TS and an increased risk of MF, possibly due to T-cell dysregulation or autoimmune processes. While the clinical course of MF is typically indolent, careful monitoring and annual dermatologic evaluations are recommended for TS patients, particularly when skin lesions are present. This is the first reported case of MF in a child with TS. This case emphasises the importance of carefully evaluating skin lesions in patients with TS and suggests considering MF as a differential diagnosis.