Case of Metastatic Basal Cell Carcinoma to Bone Marrow, Resulting in Myelophthisic Anemia

BACKGROUND: While basal cell carcinoma (BCC) remains the most common skin cancer, the incidence of metastasis is rare. Most cases of metastatic BCC have been to regional lymph nodes. Metastasis to bone marrow with myelophthisic anemia is especially rare. To our knowledge, there have been only 5 reported cases in literature. We report a sixth case. OBSERVATIONS: A 46-year-old male patient presented with an 8 × 7-cm ulcerated plaque on his chest, found to be morpheaform basal cell on pathology. Laboratory findings were notable for normocytic anemia, thrombocytopenia, and elevated LDH. Further work up with bone marrow biopsy revealed tumor cells staining positive for CK AE1/AE3, BerEP4, CK7, CD56, and PIN-4. This confirmed the diagnosis of metastatic BCC (MBCC) to bone marrow. CONCLUSIONS: Although the rate of metastasis for BCC is rare, once it occurs, prognosis is poor. MBCC remains a challenge to treat. Therefore, it is critical to resolve the primary BCC and obtain vigilant follow-up, especially in patients with multiple risk factors for MBCC.