Endocrine Abstracts

Case history: Fifty-eight years old gentleman referred to endocrinology with erectile dysfunction and decreased libido for 1 year. He denied headache or visual disturbance. His past medical history include ulcerative colitis (1998), mild asthma, anterior scleritis (2003), previous DVT (1994), Episode of steroid induced psychosis in past. He is on levothyroxine, sulfasalazine, calcium /vitamin D and long term prednisolone 4 mg (9 years). Examination reveal testicular volume of 16ml bilaterally, penile length of 7.5 cm, normal visual field on confrontation.

Investigations: His initial testosterone was 0.5, FSH 2.9, LH 0.8, Prolactin 283, IGF-1 9.3, FT4 7.2 TSH 6.26 9am cortisol 108. MRI pituitary in 2012 reveal infundibular swelling in continuity with thickened pituitary stalk.

Results and treatment: His dose of thyroxine was increased and commenced on testosterone replacement. Reported history of polyuria lasted for 1 year, 3 years ago. His repeat imaging in April 2014 showed stable appearance. In February 2016, Pituitary size increased in size, referred to tertiary centre for consideration of biopsy. Whole body MRI reveal infundibular and pituitary enlargement. ESR, CRP, ACE levels, BHCG were all normal Anti ds DNA, Ro, La, Scl, Sm/RNP negative, pANCA positive, normal visual fields. His Repeat testosterone on testosterone replacement became 16.0 and FT4 normalized to 21.3 after increment in dose of thyroxine. PET Scan December 2016 showed low grade FDG activity in the pituitary with low grade avidity in right cervical, mediastinal and right paratracheal lymphadenopathy. Right cervical lymph node biopsy showed marginal zone lymphoma. He was reviewed by haematology, whether or not pituitary abnormality is caused by low grade lymphoma, which would necessitate treatment, otherwise wait and watch. He underwent pituitary biopsy which reported IgG4 related disease. He has been referred to rheumatology for consideration of steroids +/− rituximab.

Conclusions and points of discussion: Diagnosis was Plasmocytic Hypophysitis secondary to IgG4-RD associated with hypopituitarism and marginal zone lymphoma. Prevalence of IgG4-related hypophysitis has been underestimated. It is increasingly recognized immune-mediated condition, most often occurring in middle-aged/older men. In a report of 170 patients with hypopituitarism, of whom 23 had hypophysitis, seven were diagnosed with IgG4-related hypophysitis giving a prevalence of 30 and 4 percent of hypophysitis and all hypopituitarism cases, respectively. Several types of lymphoma have been reported in patients with IgG4-RD, both in Japan and in North America. Discuss treatment options of this condition.