Progressive nodular histiocytosis: a case report and literature review

Treatment of Langerhans Cell Histiocytosis and Histiocytic Disorders: A Focus on MAPK Pathway Inhibitors

Histiocytic disorders are rare diseases defined by the clonal accumulation of a macrophage or dendritic cell origin. These disorders include Langerhans cell histiocytosis, Erdheim-Chester disease, juvenile xanthogranuloma, malignant histiocytoses, and Rosai-Dorfman-Destombes disease. These histiocytic disorders are a diverse group of disorders with different presentations, management, and prognosis. This review focuses on these histiocytic disorders and the role of pathological ERK signaling due to somatic mutations in the mitogen--activated protein kinase (MAPK) pathway. Over the last decade, there has been growing awareness of the MAPK pathway being a key driver in many histiocytic disorders, which has led to successful treatment with targeted therapies, in particular, BRAF inhibitors and MEK inhibitors.

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.

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.

Prostate carcinoma metastatic to the skin as an extrammamary Paget's disease

AIM

The current paper describes a case of prostatic adenocarcinoma metastatic to the skin presenting as an extrammamary Paget's disease, a very rare and poorly characterised morphological entity. We report a case of prostatic carcinoma metastatic to skin showing a pattern of extramammary Paget's disease which has not been clearly illustrated in the literature Case presentation: A 63 year-old man with prostatic adenocarcinoma developed cutaneous metastases after 16 years. The inguinal metastases were sessile and 'keratotic.' The tumour displayed solid, glandular areas as well as a polypoid region suggestive of extramammary Paget's disease were identified.

DISCUSSION AND CONCLUSIONS

We review the diagnostic criteria that have led to the correct histopathological diagnosis in this case. A differential diagnosis of the pagetoid spread in the skin and various forms of cutaneous metastases determined by a prostatic adenocarcinoma as well as the role of immunohistochemistry in establishing the prostatic origin are presented in the context of this case. Although, morphologically the cells presented in the skin deposits were not characteristic for adenocarcinoma of prostate, immunohistochemistry for PSA and PSAP suggested a prostatic origin.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1395450057455276.

Dermatologic manifestations of endocrine disorders

PURPOSE OF REVIEW

The diagnosis of many childhood endocrine disorders can be facilitated by an awareness of the associated dermatologic findings. In this review, we will survey examples of endocrine disorders in children that include a prominent or diagnostic dermatologic sign/symptom.

RECENT FINDINGS

A key concept is that skin findings often accompany hormonal conditions, both those of hormone excess and hormone deficiency/resistance. Some dermatologic signs may also represent the hallmark lesion, or provide the first clinical sign in childhood, for both familial tumoral and nontumoral syndromes. Moreover, skin as an endocrine organ itself may provide new avenues both to understand disease mechanisms as well as to provide targeted therapy.

SUMMARY

Early diagnosis, often aided by recognition of a keynote dermatologic lesion, may permit prompt, timely treatment that, in some cases, may even prove life saving. Conversely, when these associated signs go undetected or misdiagnosed, therapeutic intervention may be delayed unnecessarily.