A 2 month-old male infant presented with severe hypercalcemia due to parathyroid hyperplasia. A total parathyroidectomy and partial heterotopic autotransplantation were carried out. Hypercalcemia recurred two months later. Normocalcemia was re-established after removing one half of the implanted tissue. Despite two separate surgical explorations and several imaging studies, including Tc-99m-sestamibi scintigraphy, ultrasonography, and MRI, only three parathyroid glands were found. Severe pulmonary calcinosis has not previously been reported in children with PHPT. In conclusion, developmental variations of the parathyroid glands may be difficult to identify with present imaging techniques. This may pose difficulties in management of PHPT. The present report describes pulmonary calcinosis as a sequela which can cause additional morbidity in these infants.