FROM DIABETES INSIPIDUS TO SELLAR XANTHOGRANULOMA - A "YELLOW BRICK ROAD" DEMANDING TEAM-WORK

Abstract

Xanthogranulomas are inflammatory lesions exceptionally rarely occurring in the sellar region. Sellar xanthogranulomas (SXG) result from secondary hemorrhage, infarction, inflammation or necrosis upon existing craniopharyngioma (CP), Rathkès cleft cyst (RCC) or pituitary adenoma (PA), or represent a stage in xanthomatous hypophysitis evolution. "Pure SXG" are independent of a preexisting lesion. A 70 year old male patient, laryngeal cancer survivor, presented with central diabetes insipidus (CDI). MRI revealed an intra-suprasellar mass of uncertain origin. Transsphenoidal surgery resulted in an efficient lesion resection with maximal pituitary sparing. Pathological report has confirmed SXG without conclusive identification of preexisting sellar lesion. Age at presentation and gender were atypical for SXG. The most frequent presenting signs of SXG were absent. Most SXG are initially misdiagnosed as CP, RCC or PA. Preoperative clinical and radiological uncertainty may impact operative planning. Differentiating from CP is crucial, due to divergent operative target goals and prognosis. Intraoperative frozen section analysis could guide surgical extensiveness. Close collaboration must include endocrinologist, neuroradiologist, neurosurgeon and pathologist. Quantity and quality of provided tissue are essential for avoiding bias in pathohistological analysis of cystic or heterogenous lesions. Awareness is needed of new pathological entities in the sellar-parasellar region. SXG should be considered in differential diagnosis of CDI-causing sellar lesions.

Keywords: cholesterol granuloma; pituitary; polyuria-polydipsia; sellar mass; transsphenoidal surgery.

Figure 1.

MRI of sellar region – Preoperative: (A) sagittal T1w (B) coronal T1w (C) coronal T2w. – Postoperative: (D) sagittal T2w (E) coronal T1w Arrows indicate the location of sellar mass.

Figure 2.

Photomicrography of pathohistological and immunochemical specimen: (A) Giant cells of foreign body type with cholesterol clefts in the cytoplasm near normal anterior pituitary (down, right, demarcated by an oval line) (HE, x400); highlighted by CD68 immunostaining (x400) (B); A fragment of epithelium (HE, x400) (C) for which squamous nature was confirmed by nuclear p40 (D) and membranous β-catenin (E) immunostaining.