A Rapidly Enlarging Thyroid Nodule- Aspergillus Abscess

Abstract

Introduction: Acute suppurative thyroiditis is a rare thyroid disorder with high mortality often due to bacterial or fungal infection. Here we present a case of a rapidly enlarging thyroid nodule in the setting of disseminated aspergillosis.Case: A 31 year old female with lupus on immunosuppressants first presented with weakness to the emergency department with workup finding multiple pulmonary, intracranial and vertebral lesions and a left thyroid nodule. On thyroid ultrasound the nodule was solid, hypoechoic, 1.5x2.3x2.7cm with irregular margins and no echogenic foci. Thyroid function tests: Total T3 52ng/dL (80-210ng/dL), Free T4 2.26ng/dL (0.6-1.12ng/dL), TSH 0.015µIU/mL (0.45-4.12µIU/mL). The patient was started on voriconazole for disseminated aspergillosis with plan for outpatient thyroid workup. However with further brain lesion growth, the patient was readmitted with incidental finding of thyroid nodule developing into a multiloculated, septated, fluid filled 5x2.9x4cm lesion after 3 months. Fine needle aspiration of the thyroid lesion resulted in negative bacterial and fungal cultures, no malignant cells, positive fungal elements consistent with aspergillus on cytology. The patient was continued on antifungal therapy (switched to cresemba due to voriconazole side effects) with thyroid lesion regression to 2.4x0.6x1.3cm at 6 months and 1.8x1.1x1.6cm at 12 months. Her thyroid function test normalized ~ 1 month after initial set of labs and the patient remained clinically euthyroid throughout her course.Discussion: Thyroid infections are limited due to the thyroid’s high iodine content, capsular encasement and rich vascularity. Acute suppurative thyroiditis (AST) due to aspergillus is a rare finding that can present solo or as a part of disseminated infection especially in immunocompromised individuals. Early presentation is often asymptomatic with possible thyroid function test abnormalities that self resolve in a couple weeks. Occasionally patients present with obstructive symptoms or findings of thyroid storm. Diagnosis is done through fine needle aspiration or autopsy, with treatment options including surgery, antifungals or both. Due to the high mortality of fungal AST, with improved outcomes with early diagnosis, it is important to consider AST as a part of the differential diagnosis in immunocompromised patients with systemic illness.