Salt and pepper pot skull

Abstract

A 20-year-old female presented with a 3-year history of progressive hip and leg pain at rest and on walking. X-ray showed multiple lytic lesions in the long bones of the lower and upper limb. Investigations revealed a high serum calcium 12 mg/dl (N - 8.6–10.3), alkaline phosphatase 4396 IU/L (N - 44–147), and intact parathyroid hormone (iPTH) 974 pg/ml (N - 10–55) with low serum inorganic phosphate of 2.5 mg/dl (N - 3.0–4.5). X-ray skull showed the characteristic salt and pepper pot skull [Figure 1a]. It is characterized by numerous tiny lucencies in the calvarium along with a loss of definition between the inner and outer tables of the skull giving the skull a granular appearance.[12] Dual-energy X-ray absorptiometry scan for bone mineral density revealed a low Z-score of − 5.7 at distal radius, −3.8 at femoral neck, and − 4.3 at lumbar spine. A diagnosis of primary hyperparathyroidism was made. Ultrasound of the neck was suggestive of a right parathyroid adenoma. 99m Tc sestamibi single-photon emission computed tomography SPECT-CT confirmed the location of the adenoma posterior to the right lobe of the thyroid.Figure 1: (a) Salt and pepper pot skull (b) Photomicrograph of parathyroid adenoma showing chief cell hyperplasia (arrow) H and E stain 400XShe underwent excision of the parathyroid adenoma with intra-operative iPTH estimation which showed more than 50% reduction at 10 min. Postoperatively, she suffered from a hungry bone syndrome which was appropriately managed. The histopathology of the excised adenoma showing abundant chief cells [Figure 1b, arrow] was reported as parathyroid adenoma.[3] On follow-up, her serum calcium normalized and her bone pains have subsided. A thorough skeletal survey and imaging can be useful in diagnosing metabolic bone disorders. The expanded differential diagnosis of skull demineralization includes osteoporosis associated with aging and also sickle cell anemia, thalassemia, metastatic bone disease, multiple myeloma, and the lytic phase of Paget disease, but the salt and pepper appearance due to resorption of trabecular bone of the calvaria is classically described for hyperparathyroidism.[4] Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initial s will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.