Isolated primary diffuse large B-cell lymphoma in thumb, the first case in medical literature: Case report and literature review.

RATIONALE: Primary lymphoma of the bone is a rare lymphoma of bone origin. Diffuse large B-cell lymphoma (DLBCL) is the most common type of cancer worldwide. The femur is the most abundant site, followed by the pelvis, vertebrae, and humerus, and may affect one or several bones simultaneously.

PATIENT CONCERNS: A 60-year-old female visited the hospital with a history of pain and swelling in her left thumb, without a history of trauma or other symptoms.

DIAGNOSES: After conducting these tests, we diagnosed her with isolated DLBCL in the thumb.

INTERVENTIONS: We treated her according to the R-CHOP protocol with a combination of rituximab, vincristine, endoxan, doxorubicin, and prednisone for 4 cycles.

OUTCOMES: After completing the treatment, the patient achieved a complete recovery, and this result is supported by the results of normal tests and the patient's normal positron emission tomography scan.

LESSONS: Isolated thumb involvement in DLBCL is rare, and to the best of our knowledge, no similar case has been previously reported. Therefore, it is important to consider DLBCL during the differential diagnosis of similar cases.