Abstract 28

Abstract

Introduction: Xanthogranulomas are rare benign inflammatory lesion of skin with 5-10% systemic involvement. Sellarxanthogranulomas are extremely rare and can be associated with central diabetes insipidus (DI) and hypopituitarism [1]. We describe the case of a patient known to have central DI for last 11 years who developed skin lesions over face, and skin biopsy confirmed xanthogranuloma. MRI sella revealed a T1w and T2w hyperintense ovoid intrasellar lesion suggestive of sellarxanthogranuloma. Case Presentation: Fifty-eight-year-old male patient known to have central diabetes insipidus for last 11 years. Plasma osmolarity 290 mOsm/kg, urine osmolarity 132 mOsm/kg, serum sodium 142 mE/l and serum potassium were 3.6 mE/l. Water deprivation test and imaging of sella were not done at that time and trial of oral desmopressin was given, and clinical and biochemical findings of DI improved, so diagnosis of central DI was kept. Patient presented to Dermatologist 2 months back with non-pruritic nodular skin lesion at malar area. Skin biopsy revealed fibrocollagenous tissue enclosing skin appendages covered by non-keratinised stratified squamous epithelium. The subepithelial tissue show variable sized xanthomatous cell admixed with lymphocytes, neutrophils and tuton giant cells suggestive of xanthogranuloma. Patient was referred to Endocrinology Department for further evaluation. On laboratory evaluation hemogram, renal function, liver function, plasma glucose, electrolyte, calcium and angiotensin converting enzyme level were within normal limit. Hormonal evaluation revealed secondary hypothyroidism and possible growth hormone deficiency. Magnetic resonance imaging of sella revealed a well-defined 11 x 7 mm ovoid abnormal signal intensity lesion in pituitary gland appearing hyperintense on all imaging sequences causing minimal scalloping of sella, abutting right cavernous sinus, without obvious displacement of infundibulum or pituitary stalk (Figure 3a & 3b). In view of central DI, cutaneous xanthogranuloma and characteristic imaging finding diagnosis of sellarxanthogranuloma was kept. Perimetry revealed no obvious visual field defect. Patient was started oral levothyroxine 50 mcg and oral desmopressin 0.1 mg twice daily was continued. In view of no obvious compressive symptoms of sellar lesion, patient was advised yearly imaging of sella and transsphenoidal surgery whenever compressive symptoms arises. Conclusion: Sellarxanthogranulomasshould be included in differential diagnosis of central DI. It is important to have a thorough examination of skin in patient of idiopathic central DI. Follow-up imaging of sella should also be done in patient with idiopathic central DI, despite of initial normal imaging of sella.