Endocrine Abstracts

JOINT2330

Introduction: Diffuse large cell B lymphoma (DLBCL) is the most common histological subtype of non-Hodgkin’s lymphoma (30%). Its clinical presentation is highly heterogeneous and endocrine involvement is a rare manifestation. Non-Hodgkin’s lymphomas account for 3% of intracranial tumours. DLBCL is an even rarer cause of metastatic pituitary infiltration (<0.5%).

Observation: We report the case of a 54-year-old patient hospitalized for altered general condition and B symptoms. The initial work-up revealed low TSH and low T4, prompting further assessment of the other pituitary hormones, confirming the presence of thyrotropic, corticotropic and somatotropic insufficiencies, disconnection hyperprolactinaemia, and diabetes insipidus. Pituitary MRI was consistent with hypophysitis. The infectious and autoimmune work-up was unremarkable. PET-18FDG revealed pathological hypermetabolism of the left adrenal gland, pituitary gland, thyroid, subdiaphragmatic lymph nodes and subcutaneous nodules. The adrenal lesion was suspicious on contrast-enhanced CT, with plasma metanephrine levels normal. Thyroid ultrasound suggested thyroiditis with weakly positive anti-TPO antibodies. High LDH levels (936 IU/l, normal < 225), rapidly worsening pancytopenia and splenomegaly on ultrasound raised suspicion of haemopathy. A biopsy of the subcutaneous nodules finally led to the diagnosis of DLBCL. Corticotropic, thyrotropic insufficiencies and diabetes insipidus were managed with appropriate hormonal replacement therapy, and R-CHOP chemotherapy was rapidly initiated. After four treatment cycles, follow-up pituitary MRI and FDG-PET scan showed a complete morphometabolic regression of adrenal, pituitary, subcutaneous, radicular, lymph node, and bone involvement. The loss of hypersignal of the posterior pituitary gland persisted on MRI. Hormone replacement therapy remained necessary.

Conclusion: A haemopathy should be sought in cases of suspected secondary hypophysitis. The literature reports very few cases of DLBCL with synchronous involvement of several endocrine glands, and their prevalence is yet to be determined. A multidisciplinary collaboration between endocrinologists, haematologists and oncologists is essential to optimise patient management.