A Case of Familial Isolated Pituitary Adenoma Emphasizing an Often-Overlooked Aspect of Medical History

Thursday, May 4, 2023

10:30 AM – 10:45 AM

Location: Station 11, The Poster Experience

Submitter(s)

MF

Maria Fariduddin, MBBS

University of Illinois-Chicago
Bloomingdale, Illinois, United States

Primary Author(s)

MF

Maria Fariduddin, MBBS

University of Illinois-Chicago
Bloomingdale, Illinois, United States

Co-Author(s)

HC

Humberto Calero
YE

Yuval Eisenberg

Introduction:
Familial Isolated pituitary adenoma (FIPA) is a rare cause of pituitary adenoma and underscores the importance of family history and the knowledge of screening guidelines in these patients.

Case Description:
A 26-year-old female presented with secondary amenorrhea, galactorrhea, headaches and dizziness.

Labs showed:

Prolactin	501 ng/ml	(3.3-26.7 ng/mL)
IGF	391 ng/ml	(96- 301ng/mL)

MRI of the brain showed a 12 x 14 x 15 mm pituitary mass. Acromegaly was confirmed with glucose suppression test with growth hormone (GH) lowering to 1.08 ng/ml ( <0.8 ng/ml). Further history revealed a paternal cousin with gigantism diagnosed at the age of 17.

She underwent transsphenoidal resection of the adenoma which stained positive for GH and prolactin.

Post operative labs show improved levels

Prolactin

31 ng/mL

(3.3-26.7 ng/mL)

IGF

317 ng/mL

(96- 301 ng/mL)

Genetic evaluation showed a pathogenic mutation in AIP (aryl hydrocarbon receptor-interacting protein)

Labs 4 months later-

Prolactin

36.1 ng/mL

(3.3-26.7 ng/mL)

IGF

209 ng/mL

(96- 301 ng/mL)

GH

0.1 ng/mL

(0.05-8.00 ng/mL)

She was amenorrheic post surgery and with hormone replacement therapy, regular menstrual cycles ensued. Surveillance showed consistently normal IGF but prolactin levels were trending upwards.

Prolactin

80 ng/mL

(3.3-26.7 ng/mL)

A repeat MRI brain did not show any adenoma. She was started on Cabergoline and that helped with normalization of prolactin levels.

Discussion: FIPA is a rare hereditary disorder responsible for less than 2% of pituitary adenomas. Mutation of AIP is seen in 20% cases and associated with worse outcomes. The peak age of onset is between 10-30 years of age. Affected patients tend to have larger tumors than non-FIPA which increases the risk of pituitary apoplexy. GH secretion is the most common; followed by prolactin, GH-Prolactin co-secretion, non-functional and rarely TSH secreting.

It has an autosomal dominant transmission but with incomplete penetrance often skipping generations making the diagnosis even more challenging. Obtaining detailed family history in any patient with pituitary adenoma is essential in uncovering the inheritance pattern of this disease.

Screening for FIPA and AIP is recommended if patients are noted to have-

1. GH secreting adenoma diagnosed before the age of 18

2. Pituitary macroadenoma (>10 mm) diagnosed before the age of 30

3. Any pituitary adenoma with a family history of pituitary adenoma in more than one member

First degree family members of patients with FIPA and AIP need to be tested for the mutation. Patients with positive mutation are recommended to undergo screening evaluation as follows-

1. Growth assessment and evaluation for signs and symptoms of pituitary adenoma with pituitary function tests

2. Age 4-30 years: annually

3. Age 30-50 years: every 5 years

Pituitary MRI

Age 10-30 years: every 5 years

Prospective observational data shows genetic testing followed by clinical screening leads to early detection of pituitary disease which results in early interventions and better outcomes. This highlights the importance of recognition of FIPA in patients presenting with any kind of pituitary adenomas.