All patients underwent skin biopsy. The biopsy tissues were stained with hematoxylin and eosin, immunohistochemically stained for CD56, CD4, CD123, CD68, etc and used for in situ hybridization to detect Epstein-Barr virus (EBV; EBER). The patients were then followed-up from diagnosis until death.
Case 1
Patient 1 was a 59-year-old man who was admitted to the Department of Hematology at Shanxi Cancer Hospital in February 2013. He found a nodule in his right inner thigh in November 2012, and unequal nodules gradually appeared on his trunk and limbs, followed by multiple tender enlarged lymph nodes in his neck, armpits and groin. The tumors grew rapidly. Lactate dehydrogenase (LDH) levels were normal (156 U/L). A 2.0-cm lymph node biopsy from the right upper arm showed the absence of normal lymph node structure, and medium-sized diffuse lymphoid cells. Immunohistochemically, lymphocytes were positive for CD56, CD123 (Fig. 1A), CD38, LCA, CD43, CD99, and Ki67(60%), and negative for CD4, CD68, myeloperoxidase(MPO), CD3, CD20, CD21, CD10, CD5, CyclinD1, CD23, CD15, CD30, CD138, S-100, Pax-5, MUM1, CD34, Granzyme B, TIA-1, and TdT. The EBER test was negative. Bone marrow biopsy revealed diffuse lymphoid cells between the bone trabeculae, with medium-sized heterotypic nuclei. (Fig. 1B). Immunohistochemical analysis of lymphocytes indicated positivity for CD56, CD123, CD43 and Ki67 (30%), and negativity for CD4, CD68, MPO, CD3, CD20, TIA-1, and TdT. Chemotherapy was administered as the main treatment for BPDCN, but the patient developed bone marrow suppression after VDLD treatment. One month later, he was treated with CAM chemotherapy, and again showed bone marrow suppression. He subsequently developed pulmonary infection in May 2013 and central infiltration on August 8, and finally died at 7 months after his diagnosis.
Case 2
Patient 2 was a 15-year-old girl who was admitted to the Department of Hematology at Shanxi Cancer Hospital in July 2016. She inadvertently found scattered hard subcutaneous nodules on her back in May 2016. Her LDH level was increased to 348 U/L. Biopsy showed dense heteromorphic lymphoid cells throughout the dermis (Fig. 2A). Immunohistochemically, the lymphocytes were positive for CD56, CD4 (Fig. 2B), CD123, Bcl-2 and Ki67 (80%), but negative for CD68, MPO, CD3, CD20, CD30, CD43, CD5, MUM-1, CD34, TIA-1, Gramm B and CD10. An EBER test was negative. Posterior iliac puncture revealed diffuse lymphoid cells between the bone trabeculae and bone marrow, with medium-sized heterotypic nuclei, and bone marrow infiltration. Immunohistochemistry revealed that the lymphocytes were positive for CD56, CD4, CD123, and Ki67 (20%-30%), and negative for CD68, MPO, CD3, CD20, and CD38. The subcutaneous nodules subsided after anti-infective treatment but subsequently reappeared and became more severe, gradually involving the limbs and body. She was treated with CHOP and VDCLP for BPDCN, with improvement of the subcutaneous nodules and a complete bone marrow response. The patient was followed up for 17 months from diagnosis to death, after stopping treatment for economic reasons.
Case 3
Patient 3 was a 70-year-old woman who was hospitalized in another hospital. Immunohistochemical and in situ hybridization examinations were performed in the Department of Pathology of Shanxi Cancer Hospital. A biopsy from her inner left thigh demonstrated diffuse infiltrating plasmacytoid cells with nuclear deviation. Immunohistochemically, the lymphocytes were positive for CD56, CD68, and Ki67 (10%), and negative for CD4, CD123, CD3, CD20, CD10, MUM1, AE1/AE3, Desmin, S-100, and CD30. The patient was treated in another hospital and died 9 months after her diagnosis. (The main test results are shown in Table 1)
Table 1
Main test results in the three patients
Case | Site | CD56 | CD4 | CD123 | CD68 | MPO | CD3 | CD20 | Ki67 | EBER | LDH | Follow-up |
1 | Skin | + | - | + | - | - | - | - | 60% | - | 156U/L | 7 months |
Bone marrow | + | - | + | - | - | - | - | 30% | - |
2 | Skin | + | + | + | - | - | - | - | 80% | - | 348U/L ↑ | 17 months |
Bone marrow | + | + | + | - | - | - | - | 20%-30% | - |
3 | Skin | + | - | - | + | * | - | - | 10% | - | * | 9 months |
* Not checked. |