Reticulohistiocytoma is a benign giant cell granuloma of fibrogistiocytic type, a tumor of connective tissue. It is characterized by brown nodular tumor-like rashes ranging in size from a pearl to a quail egg, painless, sometimes slightly itchy, rising above the level of healthy skin. Nodes tend to merge and group or spread over the entire surface of the skin, sometimes independently involute, leaving atrophic changes. The tumor is diagnosed clinically, taking into account the results of a biopsy. Special therapy is usually not required, sometimes surgical removal is performed or corticosteroids are used in combination with cytostatics.
Reticulologistiocytoma of the skin is a benign focal (solitary or multiple) dysplasia of the reticular tissue of unknown origin, reactive histiocytosis. The pathological process has no racial and seasonal characteristics, and is not endemic. It affects mature women more often, often develops against the background of tuberculosis, the disease may be preceded by systemic polyarthropathy. According to foreign researchers, in 27% of cases with reticulologistiocytoma of the skin, cancer of the internal organs is diagnosed, while the skin tumor is prone to spontaneous involution. In Russian dermatology, the famous Moscow doctor E.S. Glavche was the first to describe a reticulologistiocytoma (fibroma) in 1902.
Western dermatological schools consider the pathological process as reactive-inflammatory granulomatosis, a rare manifestation of malignity (malignancy), a special oncology. According to Russian authors, reticulologistiocytosis is associated with tumors in 10-25% of cases, which determines the relevance of the problem at the present stage.
The essence of the pathological process is unclear. There are different views on the nature of the occurrence of reticulologistiocytoma. Some dermatologists attribute neoplasia to reactive granulomatosis, angiofibroxanthoma, others to dysplasia of reticular tissue, but most consider reticulologistiocytoma as an independent nosology of unclear genesis. At the same time, in the mechanism of pathology development, priority is given to changes in phagocytic histiocytes, related disorders in the formation and development of connective tissue. In fact, the dermis loses stability, there are anomalies in the strength of collagen structures, visually manifested by one or another pathology of the skin.
Exogenous and endogenous triggers, which most likely include genetic mutations, infections, systemic diseases, environmental conditions, irrational nutrition and stress, destabilize the constancy of the internal environment, which leads to intradermal imbalance, which is a trigger point in the development of autoimmune and allergic reactions. At the same time, the impaired adaptive ability of the skin stimulates the formation of various manifestations of dermal insufficiency.
In parallel, the ability to restore the disturbed microcirculation of the dermis and its regeneration is lost, and collagen synthesis is unbalanced. Collagen fibers are changed by collagenase synthesized by fibroblasts. Collagen degradation activates histiocytic macrophages and cytokines that stimulate inflammation in connective tissue and proliferation of skin cells. Since the connective tissue base and the microcirculation channel in the dermis are combined into one trophico-transport system, lymph circulation and blood flow are disrupted, which is visually manifested by interstitial edema with the outcome in fibrosis.
It is possible to regard the changes that are taking place not as a disease, but as a certain condition – the skin’s response to adverse factors, consider it a special transitional state from health to ill health. However, it is impossible to exclude the formation of an independent nosology with the involvement of many internal organs in the process. With reticulohistiocytoma, there are tumors of the digestive system, bronchi, uterus and its appendages, breast, as well as lymphoma, melanoma and myeloma.
Classification and symptoms
There is no classification of reticulohistiocytoma in dermatology, but to understand the essence of reticulologistiocytoma of the skin, it must be taken into account that according to the WHO International Histological Classification, it is included in the group of connective tissue tumors along with xanthomas, fibroids, atypical fibroxanthomas and juvenile xanthogranulomas.
The disease begins spontaneously, skin lesions appear, consisting of flat or ellipsoid-like brown painless nodes of various sizes (from rowan berries to quail eggs), slightly rising above the level of healthy skin. The rash of primary elements is accompanied by a non-intense itching, over time the nodes acquire a bluish hue. Some flat formations are noticeable when viewed only because of their intense coloring. Tumor-like foci have a dense elastic consistency, merging, form lumpy conglomerates of considerable size. Primary elements of reticulologistiocytomas of the skin can exist solitary, but there are also multiple tumors localized in different parts of the skin (scalp, face, back, chest, limbs, genital area).
In some cases, small nodules are located around the nail roller in the form of a coral necklace, the result of reticulohistiocytoma is nail dystrophy. Cases of cystic tendon lesions with large nodes of reticulogistiocytoma are described. In 50% of cases, skin lesions are joined by rashes on the mucous membranes of the oral cavity, upper respiratory tract, pharynx, tongue and lips. Sometimes tumor-like formations acquire the ability to spread or begin to cluster in one region, practically crawling over each other. The foci of reticulologistiocytoma of the skin have a slow growth, while the nodes in some cases spontaneously involute for no apparent reason, leaving pronounced atrophic-pigmented changes on the skin.
The most serious concomitant pathology of reticulohistiocytoma of the skin is joint damage, which precedes the visual manifestations of the pathological process. About 60% of patients turn to doctors with symptoms of symmetrical deforming polyarthritis. It is worth noting that in many cases, reticulologistiocytomas of the skin occur against the background of latent tuberculosis or oncological pathology, while the patient progressively loses weight. Lesions of muscles, lymph nodes, bone marrow and almost all internal organs are described. Involvement of the heart in the pathological process leads to a fatal outcome.
Diagnosis and treatment
The clinical diagnosis is made by a dermatologist on the basis of symptoms, a complete clinical and laboratory examination and biopsy data of cutaneous elements. Differentiate reticulohistiocytoma of the skin with rheumatoid arthritis, reticulosarcomatosis of the skin, sarcoidosis, gout, angiofibroxanthoma, reticulohistiocytosis, dermatofibroma, fibrosarcoma, juvenile xanthogranuloma. Usually the tumor does not require special treatment, sometimes after consultation with a surgeon, solitary nodes are surgically removed. Sometimes a good effect is given by treatment with corticosteroids in combination with cytostatics. In the absence of background diseases, the prognosis is quite favorable, in the presence of such pathology, the outcome depends on the severity and type of background process.