Cutaneous adult xanthogranuloma with a small portion of BRAFV600E mutated Langerhans cell histiocytosis populations: A case report and the review of published work

Histiocytoses, including Langerhans cell histiocytosis (LCH), juvenile or adult xanthogranuloma (AXG) and Rosai–Dorfman disease (RDD), are rare disorders characterized by the proliferation of cells derived from monocyte/macrophage lineages. A few cases of LCH coexisting with xanthogranuloma or RDD have been reported. The etiology of these diseases remains unclear. However, oncogenic BRAF^V600E mutations have been identified in LCH. Here, we report the case of a 26‐year‐old Japanese man with a 3‐month history of a solitary occipital nodule. No abnormality was detected in his other organs, and a total resection of the nodule was performed. Histopathological examination revealed the coexistence of LCH and AXG with prominent emperipolesis characteristic of RDD. Immunohistochemistry showed that most of the large histiocytes were positive for CD68, weakly positive or negative for S100, and negative for CD207 and CD1a, supporting the diagnosis of AXG. The tumor cells with emperipolesis did not show S100‐positive findings characteristic of RDD. The focally aggregated oval histiocytic cells were positive for CD1a, CD207, CD68 and S100, and were compatible with the immunophenotype of LCH cells. In addition, these cells were positive for BRAF^V600E mutation. The tumor cells in our patient exhibited a cellular morphology characteristic of multiple histiocytoses in a solitary cutaneous nodule, which may imply an etiological association among LCH, AXG and RDD. To our knowledge, this is the first report of a BRAF^V600E mutation‐positive case of LCH coexisting with AXG. Because patients with BRAF^V600E mutation have higher risks of multisystemic LCH and recurrence, we should carefully follow up the patient.     

Primary cutaneous localized/clearly-outlined true histiocytic sarcoma: Two long-term follow-up cases

Histiocytic sarcoma (HS) is a rare hematopoietic tumor that mainly involves extranodal sites, including the intestinal tract, skin, soft tissues and other organs. It is well known as an aggressive neoplasm that shows a poor response to therapy. However, a subset of patients with resectable disease has shown a favorable outcome with surgical treatment. Primary cutaneous HS is exceedingly rare and, to date, its long-term prognosis has thus not been well described. Here, we highlight two cases of primary cutaneous HS that showed long-term survival. Case 1 was a healthy 47-year-old woman who found a 12-mm tumor on her forehead. Case 2 was a 66-year-old woman, under follow up of a myxoid liposarcoma in her leg, who presented with a 25-mm tumor in her hypothenar eminence. Histologically, the tumors in both cases had a smooth outline with proliferating atypical tumor cells that showed histiocytic differentiation as revealed by immunohistochemistry with antibodies to CD68 (KP-1) and lysozyme in case 1; and CD68, lysozyme and CD163 in case 2. Tumor cells in case 1 had a monotonous appearance. After complete resection, cases 1 and 2 have survived for 10 and 4 years, respectively, without recurrence. To date, such patients are relatively long follow-up cases of survival from HS and highlight how a clear outline of the primary cutaneous HS tumor may be associated with its resectability and be an important factor in the assessment of its curability.     

Immunoadsorption therapy for neuromyelitis optica spectrum disorders long after the acute phase

Neuromyelitis optica (NMO) is a severe inflammatory demyelinating disease with exacerbations involving recurrent or bilateral optic neuritis and longitudinally extensive transverse myelitis. Pulse steroid therapy is recommended as the initial, acute‐phase treatment for NMO. If ineffective, treatment with plasma exchange (PE) should commence. However, no evidence exists to support the effectiveness of PE long after the acute phase. Immunoadsorption therapy (IA) eliminates pathogenic antibodies while sparing other plasma proteins. With IA, side effects of PE resulting from protein substitution can be avoided. However, whether IA is effective for NMO remains unclear. We describe a patient with anti‐aquaporin‐4‐positive myelitis who responded to IA using a tryptophan polyvinyl alcohol gel column that was begun 52 days after disease onset following the acute phase. Even long after the acute phase when symptoms appear to be stable, IA may be effective and should not be excluded as a treatment choice. J. Clin. Apheresis 30:43–45, 2015. © 2014 Wiley Periodicals, Inc.