Thyroid Dysfunction in Mycosis Fungoides: Sonographic and Laboratory Insights

Introduction: Thyroid gland affection in mycosis fungoides has been rarely reported. It occurs as extracutaneous involvement, incidentally, as a second malignancy, or as a side effect of systemic retinoids. Objective: This study aimed to specifically screen for biochemical or structural thyroid gland affection in a larger number of mycosis fungoides patients. Methods: Twenty-eight mycosis fungoides patients received a formal thyroid ultrasound examination, and evaluation of their thyroid hormones and anti-thyroid peroxidase antibody levels. Results: Hypoechogenic thyroid gland (suggesting thyroiditis) was detected in 39.3% of patients, and 39.3% had thyroid nodules. Thyroid hormones and anti-thyroid peroxidase antibodies were normal in 92.9% of patients. There was a statistically significant relation between the mycosis fungoides variant and the glandular echogenicity. Eighty percent of patients with the hypopigmented variant had hypoechoic gland, compared to 43.8 % of patients with the patch stage, and none of the patients with the poikilodermatous variant (P =0.017*). There was a statistically significant relation between the mycosis fungoides variant and DTD-TIRADS score (P =0.014*). The mean duration of mycosis fungoides was longer in patients with DTD-TIRADS III and IV and with thyroid nodules, however, without statistical significance. Patients treated by systemic psoralen ultraviolet A phototherapy, compared to narrow-band ultraviolet B phototherapy, were more likely to have thyroiditis, however, without statistical significance (P=0.265). Conclusions: We recommend regular screening for thyroid gland affection in mycosis fungoides patients, because of the possible association with thyroiditis and thyroid nodules, especially in patients with the hypopigmented variant.