High-grade squamous cell carcinoma arising in a tibial adamantinoma

Nooshin K. Dashti, Benjamin Matthew Howe, Carrie Y. Inwards, Karen J. Fritchie, Jodi M. Carter

Research output: Contribution to journalArticlepeer-review


Adamantinoma of the long bones is a rare, typically low-grade malignant tumor that frequently involves the tibia. Radiographically, adamantinoma is characteristically a lytic, intracortical, and expansile lesion with variable margins. Histologically, adamantinoma is a bimorphic neoplasm, composed of epithelial and osteofibrous elements. Herein, we describe a 72-year-old man with a long-standing tibial mass that, on imaging, rapidly developed cortical destruction with soft tissue extension. Imaging revealed no evidence of a distant site of origin. Needle core biopsy demonstrated high-grade squamous cell carcinoma, and metastasis was initially favored. However, the combined clinicoradiologic and pathologic features were most compatible with a high-grade squamous cell carcinoma arising in adamantinoma. The diagnosis was confirmed in the resection specimen. Both the age at presentation and histologic features make this case unusual and highlight a potential for misdiagnosis in the evaluation of squamous cell carcinoma–containing lesions of the tibia, reinforcing the importance of clinicoradiologic correlation in bone pathology.

Original languageEnglish (US)
Pages (from-to)123-128
Number of pages6
JournalHuman Pathology
StatePublished - Sep 2019


  • Adamantinoma of the long bone
  • High-grade
  • Metastasis
  • Squamous cell carcinoma
  • Tibia

ASJC Scopus subject areas

  • Pathology and Forensic Medicine


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