Indeterminate dendritic cell neoplasm of the skin: A 2‐case report and review of the literature

Abstract

Indeterminate dendritic cell neoplasm (IDCN) is an exceedingly rare and mostly cutaneous histiocytosis, frequently associated with other hematopoietic malignancies. We report 2 cases of multilesional cutaneous IDCN. A 55-year-old male with no associated malignancy and complete response to ultraviolet phototherapy; and a 72-year-old male with chronic myelomonocytic leukemia (CMML). Both cases showed histiocytoid cytology, positivity for CD1a and no expression of langerin or BRAF . With our patients, the literature describes 79 cases of IDCNs, including 65 (82%) with only skin involvement, 7 cases (9%) with involvement of skin and a second site, 5 cases (6%) involving lymph nodes only, 1 splenic lesion and 1 systemic disease. Seventeen cases (22%) were associated with other hematopoietic malignancies, most commonly CMML (6 cases), follicular lymphoma (4 cases) and acute myeloid leukemia (3 cases). All IDCNs associated with myeloid malignancies were limited to the skin, while most cases associated with lymphoma were limited to lymph nodes. Reported responses of cutaneous lesions to ultraviolet phototherapy are encouraging, while systemic chemotherapy is appropriate for clinically aggressive cases and treatment of associated malignancies. Recognition of the clinico-morphologic spectrum of IDCNs should prevent misdiagnoses and prompt investigation of possible associated neoplasms.

Specific cutaneous involvement of a mixed-type mature plasmacytoid dendritic cell tumor in chronic myelomonocytic leukemia

“…IDCN was shown to present as a mostly cutaneous proliferation of histiocytoid cells, predominantly in adults. As characteristic for IDCN, the patients were found to be positive for CD1a, negative for Langerin, and variably positive for S100, and the condition was strongly associated with the presence of a second hematopoietic malignancy 14 .…”

“…Histopathological examination revealed a dense infiltrate of histiocytic cells morphologically resembling Langerhanstype cells (lacking histopathological features of frank atypia) and the immunophenotype of an indeterminate cell histiocytosis (positive S100, CD1a and Langerin) 13 . Furthermore, two additional cases of a rare distinct neoplasm, cutaneous indeterminate dendritic cell neoplasm (IDCN), have been described in the literature 14 . IDCN was shown to present as a mostly cutaneous proliferation of histiocytoid cells, predominantly in adults.…”

Indeterminate dendritic cell neoplasm accompanied by eosinophilic pneumonia successfully treated by systemic steroid therapy: Report of the first case with muscular and parotid involvement and review of published work

“…Indeterminate dendritic cell neoplasm is also known as indeterminate dendritic cell tumor or indeterminate cell histiocytosis. Most of the published cases have been confined to the skin . Only rare case reports of lymph node or splenic involvement have been published .…”

“…IDCN have been described to be accompanied by various hematopoietic malignancies, including chronic myelomonocytic leukemia, acute myeloid leukemia, mast cell leukemia, chronic lymphocytic leukemia, follicular lymphoma, angioimmunoblastic T‐cell lymphoma and T‐lymphoblastic lymphoma . Coexistence of hepatocellular and basal cell carcinomas has also been reported . However, accompaniment by EP has never been reported to the best of our knowledge.…”

“…Furthermore, several deaths due to associated neoplasms have occurred. Various therapeutic approaches have been reported . Chemotherapy for associated hematopoietic malignancies has sometimes been used.…”