primary hyperparathyroidism ( phpt ) is caused by an abnormal parathyroid gland ; adenoma being the cause in > 85% of cases . secondary hyperparathyroidism is due to parathyroid gland hyperplasia resulting from end - organ resistance to pth ; the most important cause being chronic renal insufficiency . bony manifestations include diffuse osteopenia , brown tumors , subperisoteal bone resorption , pathological fractures , terminal acro - osteolysis , and salt - and - pepper appearance of the skull . though osteolytic lesions have been widely documented , osteoselerosis (  dense bones  or hyperostosis ) has been observed rarely in hyperparathyroidism . its rarity can be speculated from the fact that only a handful of literature has reported ostesclerotic lesion in cases of hyperparathyroidism . ostesclerotic lesions have been reported in some patients with secondary hyperparathyroidism ; particularly in those with chronic renal failure . focal osteosclerotic lesion usually involves pelvis , spine , skull , and metaphyseal end of the bone with simultaneous destructive or erosive lesions in other parts of the skeleton . the exact mechanism for the focal hyperostosis remains elusive . in very rare cases of phpt we report one such case of focal osteosclerosis in skull in a patient with phpt . a 35-year - male with pathological fracture in intertrochanteric region of right femur was referred to our department for a 99mtc - methylene diphosphonate ( mdp ) bone scan . the patient had a history of trivial injury at the site of fracture 1-year back . investigations revealed hypercalcemia ( 12.8 mg / dl [ 8.510.1 mg / dl ] ) , hypophosphatemia ( 1.2 mg / dl [ 2.54.9 ] ) , raised alkaline phosphatase ( 180.9 iu / l [ 37147 ] ) , and low 25-oh vitamin d levels ( 18.05 ng / ml [ 21100 g ] ) . serum intact pth ( 480.00 pg / ml [ 1472 ] ) level was raised . his skeletal survey showed a lobulated lesion in the right proximal femur with a malunited intertrochanteric fracture and a well - defined lytic lesion in the mid - shaft of right femur [ figure 1 ] . his skull x - ray showed multiple round to oval focal sclerotic changes , which is an unusual radiological presentation in phpt [ figure 2 ] . magnetic resonance imaging ( mri ) pelvis and both femori revealed a well - defined lobulated lesion involving intertrochanteric area and proximal shaft of right femur with associated expansion and cortical thinning . also rounded to oval lesion with similar magnetic resonance morphology was noted in the mid - shaft region of right femur . suggested differential diagnosis was polyostotic fibrous dysplasia and brown tumors . 99mtc - mdp bone scintigraphy revealed multiple hot spots over the frontal and parietal region of the skull [ figure 3 ] . increased tracer accumulation was also noted in the trochanteric region of right femur ( consistent with site of fracture ) and along medial border of mid - shaft of right femur ( known lytic expansile lesion as on mri ) [ figure 3 ] . x - ray hip joint and bilateral femur : a lobulated lesion in the right proximal femur with a malunited intertrochanteric fracture and a well - circumscribed lytic lesions in mid - shaft of right femur that represent the osteoclastic resorption of bone antero - posterior view skull radiograph shows multiple well - defined round to oval sclerotic lesions 99mtc - methylene diphosphonate whole body and spots bone scintigraphy revealed multiple hot spots over the frontal and parietal region of the skull . increased tracer accumulation was also noted in the trochanteric region of right femur ( consistent with the site of fracture ) and along the medial border of mid - shaft of right femur an ultrasound of the neck region done to localize the culprit parathyroid adenoma revealed no abnormality . subsequently , a 99mtc - sestamibi planar [ figure 4 ] and single photon emission computed tomography / computed tomography scan [ figure 5 ] was done , which localized the parathyroid adenoma in the lower pole region of right thyroid lobe . 99mtc - sestamibi planar images at 20 min and 2 h demonstrating parathyroid adenoma in the lower pole region of right thyroid lobe 99mtc - sestamibi single photon emission computed tomography / computed tomography scan localized the parathyroid adenoma in the lower pole region of right thyroid lobe the diagnosis of hyperparathyroidism is made clinically . an elevated pth with hypercalcemia is diagnostic of phpt . excess pth results in an increase in bone breakdown ( osteoclastic resorption ) with subsequent fibrous replacement and reactive osteoblastic activity . the most common radiologic finding in phpt are osteopenia , bone resorption ( most common is subperiosteal reabsorption - virtually pathognomonic sign of hyperparathyroidism ) , acro - osteolysis , brown tumors , erosion of the dental lamina dura , and pathologic fractures . while there are reports of diffuse or patchy osteosclerotic lesions in patients with hyperparathyroidism , discrete osteosclerotic lesions in the skull are reported rarely in these patients . reported multiple osteosclerotic lesions of the skull in a 26-year - old man with phpt . reported two children with phpt , who radiologically manifested with prominent osteosclerosis in the tibia . report two females patients with hyperparathyroidism and multiple osteosclerotic lesions of the skull with co - existing vitamin d deficiency . our patients presented with discrete osteosclerotic lesions in the skull ( a rare finding ) along with a lytic lesion in the mid - shaft of femur ( browns tumor ) . disproportionate osteoblastic activity after prolonged osteoclastic activity , an anabolic effect of supraphysiologic amount of parathormone on bone metabolism and high bone turnover in young patients are some of the plausible mechanisms responsible for the osteosclerosis . the pth level in our case is 480 pg / ml [ 1472 pg / ml ] . the age when the pathological fracture occurred was at 34 years , so the patient may have remained undiagnosed for a long time . literature reports that in some patients with hyperparathyroidism , particularly in those with chronic renal failure , osteosclerosis has been observed . this possible association was not observed in our patient as his renal parameters were within normal limits . the young age of the patient and supraphysiologic amount of pth may have been a main factor in our case . though the detection of focal osteosclerotic lesion does not alter the management of hyperparathyroidism per se . the most common differential diagnosis of multiple focal osteosclerotic lesion of the skull is metastasis . therefore , its association with hyperparathyroidism should be brought to light as it may lead to unnecessary aggressive metastatic evaluation / search for a second diagnosis .
primary hyperparathyroidism is the first differential diagnosis when a patient presents with asymptomatic hypercalcemia . 
 the symptoms of hyperparathyroidism can be as grave as skeletal , cardiovascular , and neuropsychological changes . 
 skeletal manifestations are relatively common , and patient may present with generalized or focal bone pains , fragility fractures , subperiosteal bone resorption , and osteolytic lesions like brown tumors and salt and pepper appearance of the skull . however , focal osteosclerotic lesions of the skull are rare findings in hyperparathyroidism 
 . only a few cases of associated osteosclerosis are reported in the literature . here 
 , we report a case of tc99 m sestamibi positive parathyroid adenoma with coexisting osteolytic and osteosclerotic skull lesions on tc99 m methylene diphosphonate bone scan .