Akimasa Saito, Yoshiyuki Nakamura, Ryota Tanaka, Sae Inoue, Naoko Okiyama, Yosuke Ishitsuka, Hiroshi Maruyama, Rei Watanabe, Kenji Yoshida, Akira Ishiko, Manabu Fujimoto, Satoru Shinkuma, Yasuhiro Fujisawa
DOI: 10.2340/00015555-3303

Some bone lesions are reported to mimic bone metastasis on imaging tests. Herein, we report a case of a 55-year-old Japanese man who presented with a skin tumor on the left lower extremity. He also had a history of recurrent generalized cutaneous blister and erosion formation since childhood. His skin lesions were diagnosed as cutaneous squamous cell carcinoma complicated by recessive dystrophic epidermolysis bullosa. Magnetic resonance imaging of the left lower extremity detected multiple focal bone lesions mimicking bone metastases in the left femur and tibia. However, bone biopsy revealed that the bone lesions were osteonecrosis without tumor cells. We suggest that cancer-induced osteonecrosis should be included in the differential diagnosis of bone lesions suspected of being metastases on magnetic resonance imaging.

We report a case of unusual bone lesions with osteonecrosis mimicking bone metastases of cutaneous squamous cell carcinoma in a patient with recessive dystrophic epidermolysis bullosa. In our case, it was speculated that various humoral factors carried by the feeder arteries from the primary cutaneous squamous cell carcinoma lesion and surrounding the multiple chronic wounds and scars associated with recessive dystrophic epidermolysis bullosa might be involved in the development of osteonecrosis. Our case suggests that cancer-induced osteonecrosis should be considered for the differential diagnosis of bone lesions suspected of being metastases on imaging tests.