Primary hyperparathyroidism as an extremely rare cause of secondary myelofibrosis in childhood.

Primary hyperparathyroidism (PHP) and myelofibrosis are rare entities in childhood. Myelofibrosis secondary to PHP is also extremely rare. We report a 15-year-old boy presented with generalized weakness, vomiting, and pallor. A parathyroid adenoma was detected on the left distal parathyroid gland. PHP was diagnosed together with hepatosplenomegaly and pancytopenia. Bone marrow biopsy revealed grade 3-4 reticulin fibrosis. As early as 2 months after the left distal parathyroidectomy, hematologic parameters improved without any other intervention. His liver and spleen also gradually decreased in size. We concluded that the pancytopenia was as a result of myelofibrosis from PHP.