Keywords

1 Epidemiology and Clinical Presentation

  • This lesion is also called a “cholesterol granuloma.” (See also the next Chap. 24.)

  • They have been reported to comprise a subset of lesions (up to 34 %) initially thought to be adamantinomatous craniopharyngiomas or Rathke’s cleft cysts [1].

  • They are likely to originate from Rathke’s cleft cysts or pituitary adenomas with internal hemorrhage, inflammation, or both [2].

  • They tend to occur in younger adult patients (mean, 27 years).

  • In some patients, the lesion may be part of the Erdheim-Chester disease [3].

  • They belong to a spectrum of disease that includes xanthogranulomas, xanthomatous hypophysitis, and xanthogranulomatous hypophysitis [4, 5]. (See “Inflammatory Hypophysitis” in Chap. 56.)

  • Patients have a relatively high incidence of hypopituitarism and diabetes insipidus.

2 Imaging Features

  • MRI shows a cystic sellar and suprasellar lesion with a thickened capsule [6].

  • T2-weighted MRI shows a hypointense or mixed-intensity mass with an inhomogeneous contrast enhancement pattern [6, 7].

  • Cholesterol clefts typically show high signal intensity on T1 images and low signal intensity on T2 images [2].

  • Xanthogranulomas are smaller in diameter than craniopharyngiomas, and they tend to remain primarily intrasellar [1].

  • Xanthogranulomas may extend to or invade the cavernous sinuses, an inflammatory process similar to the Tolosa-Hunt syndrome.

Fig. 23.1
figure 1

(a) Sagittal T1-weighted post-gadolinium image. (b) Coronal T1-weighted pre-gadolinium image. (c) Coronal T1-weighted post-gadolinium image. There is a lobulated cystic lesion in the sella containing T1 hyperintense material. The pituitary stalk is displaced anteriorly

Full size image

3 Histopathology

  • Extensive inflammation with no readily identifiable epithelium is seen in the majority of cases [1, 8].

  • Frequent histopathological findings include cholesterol clefts, macrophages, chronic inflammatory infiltrates, necrotic debris, foamy histiocytes, and hemosiderin deposits [4].

  • Because these lesions may not have an epithelial lining, immunohistochemistry for cytokeratins is negative [8].

  • Although they have been reported to comprise a distinct entity, it remains unknown whether they are derived from RCCs, craniopharyngiomas, and/or other lesions.

  • Features of xanthogranuloma have been reported to be more consistent with RCCs than with craniopharyngiomas; they have demonstrated a high association with squamous metaplasia of these lesions [8], as seen in Fig. 22.22d.

4 Clinical Management

  • Surgical management is the preferred primary treatment for symptomatic xanthogranulomas. Complete resection may be warranted if initial attempts at fenestration and drainage are unsuccessful.