National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Reticulohistiocytoma


Other Names:
Solitary reticulohistiocytosis; Solitary histiocytoma
Reticulohistiocytoma (RH) is a rare benign lesion of the soft tissue. It belongs to a group of disorders called non-Langerhans cell histiocytosis and is a type of reticulohistiocytosis, all of which are types of histiocytosis.[1][2] Histiocytosis is a condition in which there is rapid production (proliferation) of histiocytes (immune cells) in the skin or soft tissues.[3] The stimulus that causes the immune system to react in RH is currently not well understood.[1] RH present as a yellow to reddish-brown smooth surfaced, firm nodule or lesion on the trunk and/or extremities of the body.[2] Historically, RH has been found in young adults, with a slightly higher incidence in males.[1] RH typically resolve spontaneously over a period of months to years, are not associated with systemic disease, and do not otherwise affect health. Treatment involves surgical removal of the lesion.[4]
Last updated: 3/31/2016
While it is known that reticulohistiocytoma (RH) develop due to a rapid production of immune cells (histiocytes) in the skin or soft tissues, the cause of this process is not currently known.[5][1]
Last updated: 3/31/2016
The diagnosis of reticulohistiocytoma (RH) is made based on clinical presentation, histology, and immunohistochemistry profile. RH occur in isolation and are typically described as small, yellow to reddish-born nodules. The lesions usually are slightly elevated from the surrounding skin.[5][4][2] Detailed information on histology of reticulohistiocytoma is available through DermNet NZ, an online resource about skin diseases developed by the New Zealand Dermatological Society Incorporated.

There are several differential diagnoses for RH. It is important to distinguish RH from Rosai-Dorfman disease, juvenile xanthogranuloma, a variety of granulomatous conditions, and some malignant neoplasms, including histiocytic sarcoma, melanoma, and epithelioid sarcoma.[5]

Reticulohistiocytoma should also be distinguished from multicentric reticulohistiocytosis. [4]
Last updated: 4/1/2016
Reticulohistiocytoma (RH) typically resolve spontaneously over a period of months to years; however, surgical excision usually results in a cure.[4]

Last updated: 3/31/2016
The long-term outlook (prognosis) for Reticulohistiocytoma (RH) is good. RH is thought to represent a benign skin lesion. RH tends to spontaneously resolve over a period of months to years and affected individuals remain healthy.[4] Recurrence of RH is rare.[6]
Last updated: 3/31/2016

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Organizations Supporting this Disease

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • DermNet NZ is an online resource about skin diseases developed by the New Zealand Dermatological Society Incorporated. DermNet NZ provides information about this condition.

In-Depth Information

  • PubMed is a searchable database of medical literature and lists journal articles that discuss Reticulohistiocytoma. Click on the link to view a sample search on this topic.

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  1. Heather M. Weissman, Brent R. Hayek, Hans E. Grossniklaus. Reticulohistiocytoma of the Orbit. Ophthal Plast Reconstr Surg. August 25, 2015; 31(1):e13-e16. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4548269/.
  2. A. Tulin Gulec. Solitary reticulohistiocytoma with arborizing vessels: A new mimicker of basal cell carcinoma. Journal of the American Academy of Dermatology. January 2016; 74(1):e5-e6. http://www.ncbi.nlm.nih.gov/pubmed/26702812.
  3. Histiocytosis. MedlinePlus. 6/9/2014; http://www.nlm.nih.gov/medlineplus/ency/article/000068.htm.
  4. Reticulohistiocytosis. DermNet NZ. Dec 28, 2013; http://www.dermnetnz.org/dermal-infiltrative/reticulohistiocytosis.html.
  5. Miettinen M, Fetsch JF. Reticulohistiocytoma (solitary epithelioid histiocytoma): a clinicopathologic and immunohistochemical study of 44 cases. Am J Surg Pathol.. 2006; http://www.ncbi.nlm.nih.gov/pubmed/16625100.
  6. Philip R. Cohen, Robert A Lee. Adult-onset reticulohistiocytoma presenting as a solitary asymptomatic red knee nodule: report and review of clinical presentations and immunohistochemistry staining features of reticulohistiocytosis.. Dermatol Online J. March 17, 2014; 20(3):http://www.ncbi.nlm.nih.gov/pubmed/24656263.