Progressive nodular histiocytosis: a case report with literature review, and discussion of differential diagnosis and classification

Progressive nodular histiocytosis in a 9-year-old boy treated with cobimetinib

Progressive nodular histiocytosis is a rare variant of non-Langerhans cell histiocytosis that affects the skin and mucous membranes and displays a progressive clinical course and poor response to treatment. We describe a case of severe progressive nodular histiocytosis harboring a KRAS p.G12S mutation in a 9-year-old boy, refractory to chemotherapy, who was successfully treated with the MEK inhibitor cobimetinib. This is the first report of the use of MEK inhibition for this histiocytosis subtype in a pediatric patient.

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.

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.

A Case with Juvenile Xanthogranuloma and Progressive Nodular Histiocytosis Overlap

A patient with overlap between juvenile xanthogranuloma and progressive nodular histiocytosis is presented. He had progressive, superficial, small, yellow-reddish papules and large dermal nodules, consistent with progressive nodular histiocytosis. Histopathology showed distinctive features of juvenile xanthogranuloma. Our patient reinforces the view that progressive nodular histiocytosis is not a distinct clinical entity, but an evolutionary form of juvenile xanthogranuloma.

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

Progressive nodular histiocytosis (PNH) represents a very rare type of non-Langerhans cell histiocytosis. It is characterized by progressive appearance of papules and nodules without spontaneous resolution. We report a 60-year-old patient with novel clinical features in the form of extensive noduloulcerative lesions, ichthyotic patches, and laryngeal involvement culminating in fatal outcome prior to therapeutic intervention. Although the presenting features were baffling, histopathology and immunohistochemistry clinched the diagnosis of PNH.

Progressive Nodular Histiocytosis Associated with Eale's Disease

Progressive nodular histiocytosis (PNH) is a rare normolipemic macrophage disorder and belongs to a subgroup of non-Langerhans cell histiocytosis (LCHs) which is characterized by a progressive course with no sign of spontaneous resolution but without systemic involvement. We report a 30-year-old gentleman who presented with skin lesions all over the body associated with gradual bilateral painless loss of vision. On examination, approximately 30 to 40, skin-colored, firm, non-tender papules and nodules were noted over the body especially on the face and trunk. A skin biopsy revealed a cellular tumor in the dermis composed of oval to spindle-shaped cells, positive for CD68 but negative for S-100, CD34, CD21, CD35 and HMB45, supporting a diagnosis of spindle cell histiocytic tumor. Ophthalmic examination revealed a generalized arteriolar attenuation in both eyes. He received Tab Imatinib 400 mg OD for 5 months followed by Tab Pazopanib 800 mg OD for 4 months and both the drugs were stopped due to lack of any response in the skin lesions. We report this case due to its rarity, characteristic clinical presentation, and its association with Eale's disease. Primary treatment remains surgical excision of bothersome lesions and optimal systemic treatment is still unknown.

Nonlipidized juvenile xanthogranuloma: an unusual variant with a potential diagnostic pitfall

Juvenile xanthogranuloma (JXG) is a histiocytic inflammatory disorder that can present different histologic patterns. Classic JXG consists of sheets of foamy histiocytes and numerous multinucleated Touton giant cells. Nonlipidized JXG (NJXG) is one of the unusual variants of JXG, consisting of a diffuse monomorphic infiltrate of mononuclear histiocytes, suggesting an aggressive or malignant tumor due the high mitotic index. However, NJXG behaves clinically as classic JXG. We present an unusual case of a 6-year-old boy who presented an exophytic ulcerated nodule on the lower lip diagnosed as NJXG. The boy is currently well without recurrence three years after surgical excision.

Sinus histiocytosis (Rosai-Dorfman disease): a clinical observation

The authors characterized a heterogeneous group of a rare disease - Langerhans and non-Langerhans cell histiocytosis, and analyzed key differential and diagnostic differences between these forms of the disease. A very rare case of non- Langerhans cell histiocytosis (Rosai-Dorfman disease) in a female patient aged 63 with the subsequent spontaneous regression of eruptions was described. Key skin manifestations of the Rosai-Dorfman disease included papular eruptions of the typical intense pink color with a yellowish and brown tint. Morphologic changes were characterized by proliferation of histiocytes and accumulation of different lipids and pentalamellar markers (S-100 protein, СD 14, СD 68, lysozyme) in their cytoplasm. Though the Rosai-Dorfman disease usually involves lymph nodes, this case was characterized by unaffected nodular structures.