Laryngeal involvement with fatal outcome in progressive nodular histiocytosis: A rare case report

Progressive Nodular Histiocytosis: Report of a Case and Review of the Literature

Progressive nodular histiocytosis (PNH) is a rare condition characterized by progressive eruption of multiple yellowish-brown papules and nodules on the skin and mucous membranes. We present the case of a 37-year-old Caucasian man with gradually increased appearance of nodular lesions on the forehead and right temple. These lesions were initially diagnosed as xanthomas and did not respond to intralesional injections of triamcinolone. Additional biopsy revealed an intense dermal infiltrate of foamy mononuclear epithelioid cells with a minor admixture of plasma cells, lymphocytes, and scattered multinucleated giant cells. On immunohistochemical staining, the lesional cells were positive for CD163 and CD68 and negative for CD1a, thus confirming a mononuclear-macrophage lineage. The clinical presentation and the histological impression lead to the diagnosis of PNH. This condition could be challenging, mimicking microscopically similar lesions of the non-Langerhans cell histiocytosis group. Although uncommon, PNH stands out due to its clinical and microscopic features and should be taken into consideration in the differential diagnosis of cutaneous histiocytoses.

Effective treatment of progressive nodular histiocytosis by intermediate-dose cytarabine: a case report and literature review

BACKGROUND

Progressive nodular histiocytosis (PNH) is a rare, clinically distinct non-Langerhans cell histiocytic neoplasm affecting the skin and mucous membranes with no signs of spontaneous regression of the lesions. Patients typically have hundreds of lesions of superficial xanthomatous papules to nodules and deep larger fibrous nodules, which can be life-threatening if laryngeal mucosa was involved. So far, few cases of PNH have been reported and no effective treatment has been shown to reverse the progressive clinical course.

CASE PRESENTATION

Here we describe a case of PNH presenting as diffuse, progressively enlarging papules, nodules and even leonine appearance in a young woman. The diagnosis was confirmed by histological and immunohistochemical findings. Next-generation sequencing (NGS) showed identical missense mutation in XIAP ^Y404C and in-frame deletion in MAPK1 ^A2[6>5]. Since ERK inhibitor has not been on the market yet, the patient received chemotherapy instead. Traditional chemotherapy with intermediate-dose of cytarabine (500 mg/m² cytarabine by 3-hour infusion every 12 hours for 3 days every 5 weeks) achieved favorable therapeutic effect as confirmed by clinical symptoms and PET/CT imaging.

CONCLUSIONS

PNH is a rare, proliferative disorder with disfiguring lesions and deteriorative quality of life. Mutations in MAPK1, XIAP may play crucial roles in the pathogenesis of PNH. Intermediate-dose cytarabine can be considered as a promising treatment option for PNH patients.