Savant Deepika, Kenan Shachar, Kenan Samuel, Kahn Leonard
Department of Pathology, Hofstra Northwell School of Medicine, 6 Ohio Drive, New Hyde Park, NY, 11040, USA.
Department of Orthopaedics, Hofstra Northwell School of Medicine, 6 Ohio Drive, New Hyde Park, NY, 11040, USA.
Skeletal Radiol. 2018 May;47(5):711-716. doi: 10.1007/s00256-017-2835-y. Epub 2017 Dec 1.
A 32-year-old male presented with a right thumb lesion of 11-month duration. A clinical diagnosis of pyogenic granuloma was entertained but the lesion failed to respond to conservative therapy and eventually necessitated amputation of his thumb. MRI of the right thumb showed an ill-defined, heterogeneously enhancing, infiltrating mass within the dorsal soft tissues abutting the distal phalanx and measuring 4.2 × 2.4 × 0.7 cm. Histologically, the tumor was composed of a high-grade osteosarcoma with a chondrosarcomatous component localized within the underlying bone and a more superficial spindle cell component in the overlying soft tissue. The epidermis was focally ulcerated overlying the lesion. The key to the diagnosis was provided by intense staining of the spindle cell component for S100 protein indicative of a spindle cell melanoma. The presence of an associated osteogenic sarcomatous component established a final diagnosis of osteogenic melanoma. The localization of this element to phalangeal bone is distinctly unusual and resulted in the close resemblance to a primary osteogenic sarcoma.
一名32岁男性，右手拇指出现病变11个月。临床考虑为化脓性肉芽肿，但病变对保守治疗无反应，最终不得不截除拇指。右手拇指MRI显示，在靠近远节指骨的背侧软组织内有一界限不清、不均匀强化的浸润性肿块，大小为4.2×2.4×0.7 cm。组织学上，肿瘤由高级别骨肉瘤组成，软骨肉瘤成分位于下方骨质内，上方软组织中有更浅表的梭形细胞成分。病变上方的表皮有局灶性溃疡。梭形细胞成分S100蛋白强烈染色提示为梭形细胞黑色素瘤，这为诊断提供了关键线索。伴有骨肉瘤成分，最终诊断为骨源性黑色素瘤。该成分定位于指骨非常罕见，导致其与原发性骨肉瘤极为相似。
