An unusual case of extra-nodal interdigitating dendritic cell neoplasm: sarcoma or not?

INTRODUCTION: Interdigitating dendritic cell sarcoma (IDCS) represents an extremely rare neoplasm frequently originating from T-cell- associated dendritic antigen-presenting cells normally populating the paracortex of lymph nodes. Diagnosis is challenging due to the rarity of this neoplasm and the overlapping features with the other primary and metastatic spindle cell neoplasm, even more, when localized in an extra-nodal site. PATIENTS AND METHODS: Herein we report a case of 48 Years old woman with a six-month history of centimetric, quiet painful mass of the philtrum without other significant comorbidity. RESULTS: Histological report showed a proliferation of quiet bland spindle to plump cell, scattered multinucleated giant cell in a subtle background of lymphocytes. IHC study displays only positivity for S-100 and fine, granular scattered cytoplasmatic stain for CD68; all dendritic IHC markers were negative. Morphological and immunohistochemical analyses were consistent with extra-nodal Interdigitating Dendritic Cell Neoplasm. CONCLUSION: Interdigitating Dendritic Cell Sarcoma is a rare and challenging entity with a variable prognosis. We present a case of extra-nodal IDCS whit low worrisome histological features, emphasizing the need for further efforts to better definitely this rare neoplasm ad its potential for malignancy.

Transcriptional analysis distinguishes breast implant-associated anaplastic large cell lymphoma from other peripheral T-cell lymphomas.

Breast implant-associated anaplastic large cell lymphoma is a new provisional entity in the revised World Health Organization classification of lymphoid malignancies, the pathogenesis and cell of origin of which are still unknown. We performed gene expression profiling of microdissected breast implant-associated anaplastic large cell lymphoma samples and compared their transcriptional profiles with those previously obtained from normal T-cells and other peripheral T-cell lymphomas and validated expression of selected markers by immunohistochemistry. Our results indicate that most breast implant-associated anaplastic large cell lymphomas exhibit an activated CD4+ memory T-cell phenotype, which is associated with CD25 and FoxP3 expression. Gene ontology analyses revealed upregulation of genes involved in cell motility programs (e.g., CCR6, MET, HGF, CXCL14) in breast implant-associated anaplastic large cell lymphomas compared to normal CD4+ T-cells and upregulation of genes involved in myeloid cell differentiation (e.g., PPARg, JAK2, SPI-1, GAB2) and viral gene transcription (e.g., RPS10, RPL17, RPS29, RPL18A) compared to other types of peripheral T-cell lymphomas. Gene set enrichment analyses also revealed shared features between the molecular profiles of breast implant-associated anaplastic large cell lymphomas and other types of anaplastic large cell lymphomas, including downregulation of T-cell receptor signaling and STAT3 activation. Our findings provide novel insights into the biology of this rare disease and further evidence that breast implant-associated anaplastic large cell lymphoma represents a distinct peripheral T-cell lymphoma entity.