BACKGROUND Langerhans cell sarcoma (LCS) is a rare malignancy with poor prognosis. LCS and chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) can occur in the same diseased tissues, such as lymph nodes or skin. CASE SUMMARY A 48-year-old female Han Chinese patient was admitted for generalized lymph node enlargement for 6 years and abdominal distension for 1 wk. She was diagnosed with small B-cell lymphoma (stage IV)/CLL (Benet stage B) and received chemotherapy. She started oral ibrutinib in February 2019. She was hospitalized on June 11, 2019, and a 1.5 cm × 1.5 cm dark-red nodule with ulceration scalp lesion was found. Biopsy revealed LCS but without CLL/SLL. She was diagnosed with CLL/SLL (Binet stage C, Rai stage IV) accompanied by secondary histiocytic sarcomas and skin LCS and received cyclophosphamide, doxorubicin, vincristine, dexamethasone, and etoposide but developed severe cytopenia. She ultimately refused treatments and discharged spontaneously. She died on September 12, 2019. The literature review showed that in patients with CLL/SLL, skin lesions of LCS are accompanied by CLL/SLL. This patient was different from the previously reported cases of skin LCS in patients with CLL/SLL. CONCLUSION In this patient, the skin lesion of LCS showed no concomitant CLL/SLL.