Clinical Fellow University of Minnesota medical school Minneapolis, Minnesota, United States
Introduction : Hemophagocytic Lymphohistiocytosis (HLH) is a rare and life-threatening clinical syndrome whose pathogenesis involves immune dysregulation, leading to hypercytokinemia, ultimately leading to multi-organ damage and mortality. Pituitary involvement in HLH is extremely rare and has only been reported in three case reports. We present a case of pituitary involvement leading to central hypothyroidism in the setting of Hemophagocytic Lymphohistiocytosis(HLH).
Case(s) Description : A 59-year-old male with recent development of pancytopenia, splenomegaly, and abdominal lymphadenopathy was admitted with weakness and altered mental status. Prior oncological workup, including biopsies of the retroperitoneal lymph nodes, liver, spleen, and bone marrow, demonstrated an atypical T cell population, indicating a possible lymphoproliferative disorder. MRI of the brain demonstrated abnormal thickening and enhancement of the pituitary infundibulum. Hormonal workup revealed TSH 0.20 uIU/mL( 0.30-4.20), Free T4 0.48ng/dL(0.90-1.70), total T3 levels 57ng/dL(85-202) , Prolactin 4 ng/mL(4-15). The gonadal and growth hormone axis were not evaluated due to acute illness. Laboratory findings of LDH 504 U/l (0-250), Ferritin 64,688 ng/mL(31-409), Triglycerides 319 mg/dL(Less than 150), and bone marrow biopsy findings of hemophagocytes led to a H score of 200 points suggesting a high probability of HLH. The patient was started on a high dose of Dexamethasone for HLH and Levothyroxine for central Hypothyroidism with the improvement of his thyroid function tests. Unfortunately, the patient passed away during the same hospital course.
Discussion : HLH commonly involves the spleen, liver, and bone marrow, but rare central nervous system involvement. Three cases have been previously reported with pituitary involvement. The First case is of a 48-year-old female with intravascular large B-cell lymphoma who presented with fever and was found to have central hypothyroidism and hypogonadism. The Second case is of a 75-year-old female without primary malignancy who presented with fever and polyuria and was found to have central diabetes insipidus. The third case is of an 80-year-old female who presented with a fever and an episode of hypoglycemia and was found to have central hypothyroidism, hypogonadism, and secondary adrenal insufficiency. All cases, including ours, had MRI findings of thickening and contrast enhancement of the infundibulum as well as a common hormonal abnormality of central hypothyroidism. The pathogenesis of pituitary involvement in HLH is unclear. However, the association invites further study.
