A case of indeterminate dendritic cell tumor presenting with leonine facies

Indeterminate Dendritic Cell Tumor: A Report of Two New Cases Lacking the ETV3-NCOA2 Translocation and a Literature Review

Indeterminate dendritic cell tumor (IDCT) is a cutaneous proliferation of histiocytes that share morphologic and immunophenotypic properties with Langerhans cells. IDCT was recently included in the updated WHO classification of tumors of hematopoietic and lymphoid tissues. Recent studies have shown that some cases of IDCT demonstrate an ETV3-NCOA2 translocation, supporting the idea that IDCT is a clonal neoplasm. We report 2 new cases of IDCT at our institution lacking the ETV3-NCOA2 translocation. We also present a comprehensive review of reported cases of IDCT in the medical literature. Eighty-five cases of IDCT were reported in the literature between 1985 and 2016. The median age at diagnosis was 45 years. In contrast to Langerhans cell histiocytosis, IDCT is limited to the skin in the majority of cases (88%) and generally follows an indolent clinical course. Most reported lesions are cured with complete excision. However, the histologic features of IDCT and langerhans cell histiocytosis are similar. Conjoint immunostaining for CD1a and langerin is necessary for optimal classification.

Indeterminate Cell Histiocytosis – Case Report and Review of Literature

Introduction. Indeterminate cell histiocytosis is a rare proliferative disorder of indeterminate dendritic cells, reported in only 50 case reports so far. It is clinically presented as yellow, red or brown papules and nodules that appear in otherwise healthy adult individuals. Indeterminate cells are distinct dendritic cells of the skin that have ultrastructural similarities to the epidermal Langerhans cells but do not contain the characteristic Birbeck’s granules and they are also langerin-negative, unlike LCH. Indeterminate cell histiocytosis is an exceptional entity with variable clinical, histopathologic or immunohistochemical findings, sharing morphologic and immunophenotypic features with both Langerhans- and non-Langerhans cell histiocytoses. Case Report. We present a case of indeterminate histiocytosis in a 77-year-old man with 3-year history of asymptomatic, multiple reddish and brown papules and nodules over the entire body, including the oral mucosa. Skin biopsy was done, and histopathological analysis with immunohistochemistry was performed. The positive ICH staining of cells for CD68, CD1a, and S-100 enabled us to diagnose ICH in our patient. Also, BRAF V600E mutation was detected in tumor tissue. The treatment was started with methotrexate that was effective for 6 months, but due to the disease recurrence, further therapy with thalidomide was advised, without effect. Conclusion. Indeterminate histiocytosis is a rare disease, therefore no standardized treatment has been established and the treatment options are limited.

Indeterminate cell histiocytosis in a Chinese patient with progressive and extensive nodular lesions and mixed indeterminate cell and macrophage-monocyte lineage

Indeterminate cell histiocytosis (ICH) is an extremely rare cutaneous neoplastic disorder. It has the immunophenotypic features of both Langerhans and non-Langerhans cell histiocytosis. We report here a case of a healthy young Chinese woman who presented with disfiguring, thick, infiltrated cutaneous nodules on the face, trunk and extremities which appeared progressively over a period of 4 years. No systemic involvement has been detected so far. Results of a skin biopsy showed diffuse dermal infiltration of histiocytoid cells with indented nuclei and positive staining for S100 and CD1a and negativity for CD207 (langerin). Admixed within were some CD68-positive foamy histiocytes and multinucleated giant cells with focal expression of CD163. Although the clinical presentation is more typical of progressive nodular histiocytosis, the histology and immunoprofile is consistent with ICH. Our report adds to the limited case reports in the current literature of ICH in the Chinese population.

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

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^V600E . 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.

Indeterminate Dendritic Cell Tumor in Thoracic Spine: A Case Report

BACKGROUND

Indeterminate dendritic cell tumor (IDCT) is an extremely rare hematologic disorder with poorly understood pathogenesis. Occasionally encountered by hematologists, unusual presentations of IDCT have not been reported in the spine literature.

METHODS

We report a 51-year-old man who presented with a 3-month history of progressively worsening axial thoracic back pain radiating to his sides. Magnetic resonance imaging revealed a 3-cm enhancing mass at the T9 vertebral body with an exophytic component causing significant canal stenosis. Initial percutaneous biopsy revealed histiocytic sarcoma.

RESULTS

The patient underwent exploratory thoracotomy and en bloc resection of the lesion with T8-10 fusion. Final pathology results revealed IDCT with fibrosis. IDCT immunostaining was partially positive for Langerhans cell marker (positive for S100 and CD1a, but lacked Birbeck granules and Langerin stain) and partially positive for blastic plasmacytoid dendritic cell neoplasm. Additionally, it was positive for CD45, CD68, and CD163. Lymphadenopathy was absent in this patient.

CONCLUSIONS

Although first reported in the 1980s, IDCT has been omitted from most classifications owing to its rarity. Hematologists have debated the cell of origin; it is believed to comprise pre-Langerhans cells, as Birbeck granules are acquired after migration to the epidermis. IDCT remains of indeterminate origin. We report the first case of spinal IDCT. Familiarity with the histologic features is warranted to ensure accurate diagnosis and appropriate treatment.

Multiple Familial Trichoepitheliomas Presenting as Leonine Facies

Trichoepithelioma is a benign tumor of follicular unit. It has been rarely described as the cause of leonine facies. We are presenting a classical case of multiple familial trichoepitheliomas (MFTs) with characteristic histopathological features leading to leonine facies.