POS-181 RARE INVOLVEMENT OF THYROID GLAND WITH ASPERGILLOSIS IN RENAL TRANSPLANT RECEPIENT

Abstract

Aspergillosis is an infection caused by saprophytic fungi normally found in soil and decaying vegetation. Although there are more than 1000 Aspergillus species, only Aspergillus niger, A. fumigatus and A. flavus are pathogenic. Though disseminated invasive aspergillosis is seen in 20 % cases, but reports of aspergillosis that has disseminated to the thyroid gland, presenting as vocal cord palsy and treated in renal transplant patients, as in this case, are extremely rare. We present a case of 47 years old male who underwent live related kidney transplantation. 3 months post-transplant, he had acute cellular rejection which was treated with pulse methyl prednisolone and anti-thymocyte globulin. He also had recent admission for Klebsiella pneumonia related consolidation which was treated with antibiotics. Though the sputum also showed few fungal hyphae but as he was responding to antibiotics, no antifungal was added. In this admission he was admitted for hoarseness of voice which was diagnosed due to left vocal cord palsy on laryngoscopic examination. MRI neck revealed hyperintense lesion most probably colloidal nodule on left mid and lower pole of thyroid on T2 imaging. FNAC yielded fungal hyphae with regular septation and acute branching, morphologically consistent with aspergillus. Galactomannan assay was positive. Thyroid profile was normal. Sputum for fungal stain also yielded hyphae of filamentous fungi. He was started on oral voriconazole and was serially monitored with USG neck and galactomannan assay. Fungal infections of the thyroid are extremely uncommon. A rich blood and lymphatic supply, well developed capsule and high iodine content of the gland are various mechanism of resistance to infection. Most of thyroid lesions of invasive Aspergillosis are described as focal abscesses, patchy haemorrhagic lesions due to vascular invasion or diffuse necrotizing thyroiditis. In patients with thyroid Aspergillosis, local inflammation and direct tissue destruction caused by fungi can cause thyroid hormones to leak into the bloodstream, sometimes leading to thyrotoxicosis. Though in our case patient had normal thyroid profile and he was asymptomatic apart from hoarseness of voice.The galactomannan assay which detects galactomannan antigen, which is component of Aspergillus cell wall, can detect aspergillosis before symptoms appear, but sensitivity and specificity in solid organ transplant patients are lower than in haematological patients. Though surgical options can be tried whenever the lesion is accessible like in this case but voriconazole is the most effective drug for disseminated and invasive Aspergillosis. It inhibits the activity of cytochrome P450-3A4; that’s why the tacrolimus dose should be reduced to prevent nephrotoxicity. Due to various innate resistance mechanism, fungal infections of the thyroid are extremely uncommon. Aspergillosis in our case presented as change in voice. It was diagnosed by FNAC of nodular lesion of thyroid gland. Though surgical excision can be tried but as in this case, it can be treated with voriconazole with serial galactomannan and ultrasonographic monitoring.