A red soft to firm swelling on the sternum that on biopsy shows specific histology leads us to consider certain diagnoses. The options provided are:
Hemangioma
Osteochondroma
Osteoid osteoma
Paget disease
To identify the correct diagnosis, let's analyze each option:
Hemangioma: This is a benign tumor composed of blood vessels, often presenting as a red, soft to firm swelling due to its vascular nature. On biopsy, it typically shows a proliferation of blood vessels, sometimes filled with blood.
Osteochondroma: A benign bone tumor that often occurs at the growth plates in children and teenagers. The histology would show a cartilage cap and bone, not matching a red swelling description.
Osteoid osteoma: A small, benign bone tumor characterized by a nidus of osteoblasts surrounded by reactive bone. Typically presents with localized nocturnal pain but is unlikely to appear as a red swelling.
Paget disease: A chronic disorder causing bone expansion and weakening but would not present with a red soft swelling or typical vascular features in histology.
Considering the presentation and biopsy results, the red swelling and vascular characteristics strongly point towards Hemangioma as the diagnosis, since these features align most closely with what is described.
