Spinal polyostotic fibrous dysplasia in two adults: Does only biopsy unravel the mystery?
A 44 year old male presented with insidious onset gradually progressive symmetrical, inflammatory polyarthralgia predominantly involving small joints of hands of six months duration; diagnosed and treated as seronegative arthritis with analgesics and methotrexate. There was no history of bone pains, deformity of the joints/bones or systemic symptoms. General and systemic examination was unremarkable except arthritis, of which clinical disease activity index was 32 (maximum of 76; ≥21 indicating severe disease activity).\nLaboratory evaluation revealed a haemoglobin of 15.1 g/dL, total leucocyte count of 8,700 cells/cu.mm, normal differential count, erythrocyte sedimentation rate of 45 mm fall at one hour (0-10). All his biochemical parameters were normal except for elevated alkaline phosphatase – 350 IU/L. C-reactive protein was 12 mg/dL (<10), rheumatoid factor was 7.0 IU/mL, anti-cyclic citrullinated peptide antibody was 4.2 IU/mL (<5), anti-nuclear antibody was 4.8 U (<20), anti-dsDNA was 32.2 IU/mL (<35), HLA-B27 negative and anti-neutrophilcytoplasmic autoantibodies were negative. Skeletal survey revealed multiple mixed lytic and sclerotic lesions in vertebral bodies and posterior elements from 8th thoracic to 5th lumbar vertebra [] and expansile lytic lesions were seen in 8th, 11th and 12th rib. Magnetic resonant image (MRI) of the spine showed destructive changes in the vertebral bodies and posterior elements from 8th dorsal vertebrae to 5th lumbar vertebrae. Bone scan showed increased uptake in the areas described above []. His bone mineral density (BMD) by dual energy X-ray absorptiometry (DXA) was normal (T-score-0.9 and Z-score-0.4 at lumbar spine). Serum electrophoresis didn’t reveal M band and bone marrow aspiration was cellular and reactive. Oncological markers such as serum prostate specific agent (PSA), carcino-embryogenic agent (CEA) and carbohydrate antigen (CA)-19.9 were within normal limits. An open biopsy from left 8th rib revealed the diagnosis of fibrous dysplasia in 2005. Severity of fibrous dysplasia as interpreted by bone scan[] was 0.66. There was no evidence of café-au-lait spots and his endocrinal evaluation including thyroid adrenal and pituitary function tests were normal.\nHe was started on intravenous pamidronate, along with calcium and vitamin D supplements. Six months later he noted weight loss of 12 kgs in spite of preserved appetite. He also had noted palpitations, heat intolerance and tremulousness. There was no goitre, ophthalmopathy or dermopathy. His thyroid function test was consistent with thyrotoxicosis [Tri-iodothyronine (T3) - 2.9 mg/dL (0.9-2.6), thyroxin (T4) -20.0 μg/dL (5.5-13.0) and thyroid stimulating hormone (TSH) - 0.04 μIU/mL]. Thyroid antibodies were negative. 99mTechnicium scan showed homogenous increased uptake in the thyroid with suppressed salivary uptake suggestive of hyperthyroid status. He was also detected to have diabetes mellitus (DM) by oral glucose tolerance test (OGTT, fasting 142 mg/dL and two hour 219 mg/dL). There was also evidence of transaminitis (SGOT/SGPT – 134/175) which persisted even after stopping methotrexate and test was positive for anti-HCV antibodies; however HCV viral count was zero. Modified KnodellIshak score showed grade 1/18 and stage 1/6 on liver biopsy. In view of association of hyperthyroidism with fibrous dysplasia and underlying HCV infection he was radioablated with 10 mCi of radioiodine and in addition advised diabetic diet. He developed post ablative hypothyroidism three months later and has been on thyroxine replacement since then. Once euthyroidism was achieved, result of repeat OGTT was suggestive of DM and started on metformin. Presently he is receiving zoledronic acid 4 mg twice yearly, methotrexate 7.5 mg weekly, thyroxine, metformin, calcium and vitamin D supplements. His annual bone scans have showed stable disease. At his latest review 18F-FDG PET was performed for the first time which showed both active and healed osseous lesions []. He has not sustained any fracture till date.