A case of interdigitating dendritic cell sarcoma studied by whole-exome sequencing

Nonlymphoid Hematopoietic Diseases Presenting in Bone, Soft Tissue, and Other Extranodal Sites

Context.—

Although rare in everyday practice, the initial presentation of hematopoietic neoplasms other than lymphoma in the musculoskeletal system and other extranodal sites can generate challenging diagnostic problems for surgical pathologists.

Objective.—

To review the morphologic and immunophenotypic features of various nonlymphoid hematopoietic diseases presenting at extranodal sites, with emphasis on the inherent diagnostic pitfalls and differential diagnoses of these entities to aid surgical pathologists in their accurate recognition.

Data Sources.—

Cases reviewed herein represent both in-house and consult cases seen at our institution between 2010 and 2021.

Conclusions.—

Entities that present in this way include myeloid neoplasms and histiocytic/dendritic cell neoplasms. These tumors commonly cause nonspecific symptoms, and their histologic appearance can overlap with a variety of benign neoplasms and reactive processes. This can lead to delay in diagnosis and intervention with potentially lifesaving therapy; thus, accurate and expedient recognition is of paramount importance.

Interdigitating Dendritic Cell Tumor of Submandibular Lymph Node: Case Report and Literature Review

Dendritic cells (DCs) are key arms of immune system, which act in antigen presenting processes, and are considered as a bridge between innate and adaptive immune responses. DCs are found in both lymphoid and non-lymphoid organs. They are called interdigitating dendritic cells (IDCs) in secondary lymphoid organs. IDCs lack lineage surface markers and are positive for S-100 and vimentin. IDC sarcoma (IDCS) is a very rare neoplasm, which mainly affects lymph nodes, though there are reports of extra-nodal involvement. IDCS is thought to have poor prognosis. Although there is no consensus on the treatment modalities, such options as radical surgery, chemotherapy, and radiotherapy are performed depending on severity and site of the lesion. In this study, we present a case of IDCS in a 53-year-old male with a history of several skin lesions and prior diagnoses of basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and metatypical carcinoma (MTC).