Postoperative expression of Cushing disease in a young male: metamorphosis of silent corticotroph adenoma?

Abstract

Summary: Silent corticotroph adenoma (SCA) is an unusual type of nonfunctioning pituitary adenoma (NFA) that is silent both clinically and biochemically and can only be recognized by positive immunostaining for ACTH. Under rare circumstances, it can transform into hormonally active disease presenting with severe Cushing syndrome. It might often produce diagnostic dilemma with difficult management issue if not thoroughly investigated and subtyped accordingly following surgery. Here, we present a 21-year-old male who initially underwent pituitary adenomectomy for presumed NFA with compressive symptoms. However, he developed recurrent and invasive macroadenoma with severe clinical as well as biochemical hypercortisolism during post-surgical follow-up. Repeat pituitary surgery was carried out urgently as there was significant optic chiasmal compression. Immunohistochemical analysis of the tumor tissue obtained on repeat surgery proved it to be an aggressive corticotroph adenoma. Though not cured, he showed marked clinical and biochemical improvement in the immediate postoperative period. Anticipating recurrence from the residual tumor, we referred him for cyber knife radio surgery.

Learning points: Pituitary NFA commonly present with compressive symptoms such as headache and blurred vision. Post-surgical development of Cushing syndrome in such a case could be either drug induced or endogenous. In the presence of recurrent pituitary tumor, ACTH-dependent Cushing syndrome indicates CD. Rarely a SCA presenting initially as NFA can transform into an active corticotroph adenoma. Immunohistochemical marker for ACTH in the resected tumor confirms the diagnosis.

Keywords: 2019; ACTH; Acanthosis nigricans; Adolescent/young adult; Asian - Bangladeshi; Bangladesh; Blood pressure; CT scan; Central obesity; Corticotrophic adenoma; Cortisol; Cortisol (plasma); Cortisol, free (24-hour urine); Cushing's disease; Cushing's syndrome; Dexamethasone; Dexamethasone suppression (high dose); Dexamethasone suppression (low dose); Dorsocervical fat pad*; Dyslipidaemia; Error in diagnosis/pitfalls and caveats; FSH; Facial plethora; Facies - moon; Fundoscopy*; Gamma knife radiosurgery; Glucocorticoids; Histopathology; Hypogonadism; Hypogonadotrophic hypogonadism; Immunohistochemistry; Immunostaining; Leukocytosis; Liver function; MRI; Male; Non-functioning pituitary adenoma; Obesity; October; Ophthalmology; Pathology; Pituitary; Prolactin; Radiotherapy; Resection of tumour; Striae; Supraclavicular fat pads; Surgery; Testosterone; Transsphenoidal surgery; Visual disturbance; Visual field defect; Weight gain.

Figure 1

MRI of pituitary macroadenoma in relation with surgery. (A) Before 1st operation (sellar mass with suprasellar extension); (B) after 1st operation (residual sellar mass with postoperative fluid collection); (C) before 2nd operation (recurrence of the tumor); (D) after 2nd operation (partial empty sella with residual mass).

Figure 2

Facial appearance and abdominal striae of the patient. (A) Before first surgery (normal); (B) before second surgery (Cushingoid); (C) 1 month after second surgery (regression of Cushingoid appearance).

Figure 3

Photomicrographs of the pituitary adenoma showing (A) PAS stain; immunopositivity for (B) FSH (4+) (C) BER EP 4 (EP 155) and (D) ACTH (2+).