A 3-year-8-month old male presented with a violet skin lesion and a swelling below his right knee which was first noticed at an age of 7 months. The swelling gradually increased in size over the next two years and was associated with pain, low grade intermittent fever and decreased appetite. At this time a radiograph was obtained which revealed lytic areas involving head and proximal shaft of right tibia and fibula (images not shown). An exploration of lesion was done in December, 2015 and histopathology revealed fibrofatty tissue with evidence of chronic inflammation. A provisional diagnosis of osteomyelitis was made and treatment with broad spectrum antibiotics was initiated. However, there was no symptomatic relief and the swelling progressed in size. After a repeat imaging, 2nd debridement was done in June, 2016 (Fig. 1a) and antibiotics were continued. Histopathology on this occasion showed normal bone with few areas of necrosis and no evidence of granuloma or malignancy. Despite surgery, the symptoms persisted and 3rd debridement was done in December, 2016. Results were again disappointing and he was started on empirical ATT from April, 2017 (Fig. 1b).
He presented to our hospital in August, 2017. The child had a swelling below knee over the right leg which was hard in consistency. The skin over the tumor was of violet color with increased temperature. The child had a poor nutritional status. His complete blood counts were suggestive of anaemia, leucocytosis and normal platelet count. Liver and kidney function tests were normal. Peripheral smear revealed microcytic and hypochromic RBCs. Bone marrow studies were normal. Workup for primary immunodeficiency, bacterial/fungal infection and tuberculosis was negative. A radiograph of right leg showed lytic sclerotic destructive lesion with midzone of transition seen involving right proximal tibia and fibula with soft tissue component (Fig. 1c). MRI done in 2016 and 2017 (Fig. 2) revealed destruction of the right proximal tibia and fibula with marrow oedema, oedematous changes in surrounding soft tissue, atrophy of the calf muscles and a sinus tract due to prior surgical interventions. A bone biopsy was done which showed fibro-collagenous tissue with mild chronic inflammation. He was considered to have chronic tubercular osteomyelitis and continued on ATT till August, 2018 with no response. A repeat biopsy of the lesion in August, 2018 showed a tumor with nodular architecture. Immunohistochemistry was positive for CD34, FLI-1 and CD31 (Fig. 3). It was negative for EMA, desmin and myogenin. Skin biopsy showed features of acanthotic epidermis with dense fibrosis in the dermis and similar tumor in deep dermis. Bone biopsy had infiltration of bone by similar tissue. Fat biopsy showed fibroadipose tissue with vascular proliferation. A diagnosis of KH was made and he was referred to our sarcoma clinic in September, 2018. He was started on treatment with propranolol at a dose of 0.6 mg/kg twice a day for 1 week followed by 1.1 mg/kg for 2 weeks and 1.7 mg/kg thereafter along with prednisone at 2 mg/kg. On follow-up after a month child was better; with a slight decrease in size of swelling and pain and was able to sleep without analgesics. His appetite improved. On follow up at 3 month he had an excellent clinical response. Imaging with MRI at 5 months revealed a near complete resolution. He developed cushingoid features on steroids which resolved on tapering of steroids.
The treatment plan for surgery was discussed with parents. However, parents have preferred to defer any extensive surgery and decided to continue with medical management.