Ectopic Cushing's syndrome secondary to olfactory neuroblastoma

Abstract

We present the case of a patient with Cushing's syndrome secondary to ectopic ACTH secretion. A MR of the head showed a left-sided nasal mass extending down from the cribriform plate. The patient underwent endoscopic resection with nearly complete removal of the mass. Histological examination showed an ACTH-secreting olfactory neuroblastoma (ONB). The patient's cortisol levels returned to normal range after surgery and have remained normal for over a year. ONB is a rare cause for ectopic ACTH secretion. This case highlights the diagnostic and management difficulties in patients with ectopic ACTH secretion, and provides a brief review of ONB.

Keywords: ACTH; Cushing’s; Ectopic; Olfactory neuroblastoma.

Fig. 1

Sagittal T1-weighted MRI with gadolinium contrast (a) and Coronal T2-weighted MRI (b) revealing an enhancing nasal mass extending down from the cribriform plate of the anterior cranial fossa (open arrow), with the presence of a normal pituitary gland (solid arrow)

Fig. 2

Nasal mucosa appears to be infiltrated by tumour (a haematoxylin and eosin, ×10); the lesion has lobular and sheet-like architecture (b haematoxylin-eosin, ×10) and consists of moderately atypical cells with scanty cytoplasm (c haematoxylin-eosin, ×20). Neoplastic cells are intensely positive for synaptophysin (d immunoperoxidase, ×10); the immunoreaction for S-100 protein highlights sustentacular cells (e immunoperoxidase, ×20); the present of focal neuropil is shown with the immunoreaction for neurofilament proteins (f immunoperoxidase, ×20); several tumour cells are positive for ACTH (g immunoperoxidase, ×4); there is no expression of T-pit (h immunoperoxidase, ×20); normal adenohypophysis used as control shows normal T-pit expression (i immunoperoxidase, ×20)