Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy that can manifest with skin nodules and erythematous plaques. In most cases BPDCN progresses rapidly, causing multiple skin lesions and also affecting internal organs and bone marrow, warranting initiation of systemic therapies or hematopoietic stem cell transplantation (HCT). Although not curative, radiotherapy for isolated lesions might be indicated in case of (imminent) ulceration and large or symptomatic lesions. To this end, doses of 27.0–51.0 Gy have been reported. Here, we present the case of an 80-year-old male with BPDCN with multiple large, nodular, and ulcerating lesions of the thorax, abdomen, and face. Low-dose radiotherapy of 2 × 4.0 Gy was administered to several lesions, which resolved completely within 1 week with only light residual hyperpigmentation of the skin in affected areas and reliably prevented further ulceration. Radiotoxicity was not reported. Therefore, low-dose radiotherapy can be an effective and low-key treatment in selected cases of BPDCN, especially in a palliative setting, with a favorable toxicity profile.

母细胞性浆细胞样树突状细胞肿瘤（BPDCN）是一种罕见的血液系统恶性肿瘤，可表现为皮肤结节和红斑。在大多数情况下，BPDCN 进展迅速，导致多处皮肤损伤，还影响内脏和骨髓，需要开始全身治疗或造血干细胞移植 (HCT)。虽然不能治愈，但在（即将发生）溃疡和大的或有症状的病变的情况下，可能需要对孤立的病变进行放射治疗。为此，已报告的剂量为 27.0-51.0 Gy。在此，我们介绍一名患有 BPDCN 的 80 岁男性病例，其胸部、腹部和面部有多处大的、结节性和溃疡性病变。对多个病灶进行了 2 × 4.0 Gy 的低剂量放射治疗，1 周内完全消退，受影响区域的皮肤仅残留轻微色素沉着，并可靠地防止了进一步的溃疡。没有报道放射毒性。因此，低剂量放疗对于特定的 BPDCN 病例可能是一种有效且低调的治疗方法，尤其是在姑息治疗中，并且具有良好的毒性特征。