Endocrine Abstracts

Introduction: Treatment using radioactive iodine (RAI) is used in several thyroid diseases, including differentiated thyroid carcinoma (DTC). The most frequent adverse effects include acute gastrointestinal symptoms, sialadenitis, xerostomia, cervical pain, and cervical swelling. Chronic symptoms such as obstruction of the salivary ducts, pulmonary fibrosis or other primary malignant diseases are also described. A single case of change in tongue pigmentation / lingua villosa nigra following treatment with RAI for DTC, was described in a recent case report. We present a similar case of change in tongue pigmentation after treatment with RAI, also associated with nails darkening.

Case report: A 54-year-old black woman followed in our Endocrinology Department for papillary thyroid carcinoma, diagnosed at the age of 47, underwent total thyroidectomy and adjuvant treatment with 100mCi of RAI. Due to pulmonary metastasis, she was treated with a second RAI cycle of 150mCi. At that time, she was medicated with levothyroxine 125 mg/day and was asymptomatic. No relevant laboratory results were observed (hemoglobin 14.1 g/dl, leukocytes 4890x10^3/µL, platelets 374x10^3/µL, TSH <0.02 µUI/ml T3 139 ng/dl, antithyroglobulin antibodies <40 UI/ml, thyroglobulin 46.3 ng/ml). The treatment was uneventful and post-treatment body scintigraphy did not reveal any uptake, including pulmonary uptake. Two days later, she presented a striated melanonychia, discolored tongue, edema of both hands, generalized joint pain, as well as abdominal pain. These complaints spontaneously reversed over the course of two weeks. One month after the onset of symptoms, on observation, she presented on good condition, afebrile, maintaining a slight swelling of the hands and striated melanonychia on the first fingers of both hands. Her teeth were in good condition and did not presented halitosis. On the dorsal side of the tongue, a diffuse black pigmentation was observed, with discolored areas, but without fissures nor erythema. A salivary gland scintigraphy revealed severe functional and secretory impairment of the left parotid gland and a slight secretory impairment of the submandibular glands. The patient maintained a close follow-up and at the last observation, seven months after RAI treatment, her pain had improved and her tongue had a normal pigmentation, although she maintained striated melanonychia.

Conclusion: We present a case of parotid gland dysfunction associated with lingua villosa nigra as well as other unspecified symptoms, secondary to RAI, similar to a recently described case. However, striated melanonychia was also present and, to our knowledge, it is the first case describing such condition following treatment with RAI.