SOFT Case 5 (15th Jan 2005)

History: 48 y / female with history of pain in left leg.

X - Ray revealed a lytic lesion in the left tibia.
Serum Calcium 12 mg / dl
Alkaline Phosphatase 155 U / L

The lesion was biopsied. The H & E stained slide composite images are shown.
Composite 1: A & B are x100 and C & D are x 400
Composite 2: E & F are x 100 G & H are x400

Presented by Dr. Neha Dahiya
Consultant Pathologist, KG Hospital, Coimbatore.

nehadahiya@yahoo.com

ANSWER CASE 5

Eight colleagues responded and the various diagnoses received were:
1) Solid Variant of aneurysmal bone cyst
2) Giant cell tumour
3) Metaphyseal fibrous defect in elderly
4) Osteofibrous dysplasia
5) Osteoblastoma
6) Giant Cell Granuloma
7) Brown tumour of Hyperparathyroidism.

The final diagnoses we gave was - Brown tumour of Hyperparathyroidism.

Congratulations to Dr Jayaram, Dr SK Kaushik, Dr KP Aravindan who gave the correct answer and also to Dr Shaila Shah who got it correct on the second attempt.

When we received the specimen (outside referral) the only information provided was lytic lesion in tibia. The histology made me think of Brown tumour / giant cell granuloma / solid variant of aneurysmal bone cyst. On contacting the referrring physician he gave further information of.... Location - Diaphysis Mildly elevated Serum calcium and incresed serum alkaline phosphatase. The age and location went against the solid variant of ABC. Giant cell tumour (osteoclastoma) was also ruled out on basis of location. We sent the impression as Brown tumour and the DD of giant cell granuloma which is the closest differential and cannot be distinguished on histology alone (as mentioned by Dr Jayaram)

Later the patient came to our hospital with a similar lesion in the radius and her Parathormone was found to be elevated. Hypercalcaemia is the most constant marker for parathyroid dysfunction, sometimes it may be normal. The diagnosis requires clinical , biochemical and histological correlation along with XRay findings. The synnonymas are Osteitis fibrosa cystica and von Recklinghausen's disease of bone.

The images show both osteoblastic and osteoclastic activity. Osteoclastic burrowing in bone matrix is seen. Peritrabecular fibrosis is present.

Composite 1:
A) x100 and C) x 400 shows osteoblastic rimming
A) also shows fibrosis around the bone
B) x100 and D) x 400 show osteoclastic activity

Composite 2:
E and F) low and high magnification area with osteoblastic activity
G and H) high power view with mononuclear cells and osteoclastic giant cells.