Mastocytomas
Mastocytomas are skin lesions associated with mastocytosis, a condition marked by an abnormal proliferation of mast cells, a type of white blood cell. These growths, which can occur as solitary or multiple lesions, primarily affect young children, often before the age of six months, and are rare in adults. Mastocytomas typically appear as nodules ranging from one to five centimeters, often located on the extremities, and may be asymptomatic or intermittently itchy and swollen when stroked. While these lesions usually resolve on their own by adolescence, they can sometimes necessitate treatment, particularly if they cause discomfort or complications. Treatment options include local therapies such as PUVA therapy, potent topical steroids, and, in rare cases, surgical excision. Mastocytomas are part of a spectrum of cutaneous diseases, alongside conditions like urticaria pigmentosa and diffuse cutaneous mastocytosis. The overall incidence is low, with mastocytosis affecting approximately one in ten to twenty thousand people, and the lesions can be mistaken for other skin conditions, such as atopic dermatitis. Understanding mastocytomas is important for effective diagnosis and management, highlighting the need for awareness and appropriate care.
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Mastocytomas
ALSO KNOWN AS: Mast cell tumor
RELATED CONDITIONS: Mastocytosis
DEFINITION: Mastocytomas are lesions found in mastocytosis, a condition characterized by an abnormal growth of mast cells (a type of white blood cells). These growths or lumps may contain muscle, skin, or subcutaneous tissue. Mastocytomas do not lead to the hematogenous spread of mast cells. There is no known association between mastocytomas and a predilection to develop mast cell leukemia.
Risk factors: Mastocytomas typically develop only in people with mastocytosis.
Etiology and the disease process: Mast cells are ubiquitous throughout the body in almost all body tissues. They release proinflammatory mediators such as histamine on activation. Mastocytosis may be limited to the skin, in which case it is referred to as cutaneous mastocytosis, or may involve systemic organ systems, in which case it is called systemic mastocytosis. Mastocytomas, along with urticaria pigmentosa, diffuse cutaneous mastocytosis, and telangiectasia macularis eruptiva perstans (TMEP), make up the spectrum of cutaneous disease. Accumulations of mast cells in the skin result in these conditions.
Mastocytomas can appear as solitary or multiple lesions and typically affect only children before the age of six months. Mastocytomas more commonly appear as solitary lesions, and if a second lesion or multiple lesions develop, they typically do not occur more than two months after the first lesion. They are rare in adults because they usually resolve early in life. Although mastocytomas most commonly are localized to the skin, other organs, such as the gastrointestinal system, may be affected. They are nodular, usually range in size from three to four centimeters, and frequently occur on an extremity.
Incidence: Mastocytomas are rare. Mastocytosis impacts aproximately one in ten to twenty thousand people. It is sometimes confused with atopic dermatitis.
Symptoms: Lesions may be asymptomatic or may intermittently become itchy, red, and swollen if the lesions are stroked. More commonly, lesions are asymptomatic and range from one to five centimeters in diameter.
Screening and diagnosis: The lesions typically demonstrate Darier’s sign, which occurs when a lesion is stroked and the surrounding area becomes itchy, red, and swollen. On histological examination, mastocytomas show marked tumorlike aggregates of mast cells throughout the dermis.
Treatment and therapy: Mastocytomas that cause mechanical problems or systemic problems can be treated locally with PUVA therapy (psoralen combined with long-wave ultraviolet light). Potent topical steroids under occlusive dressings are also utilized. Surgical excision is also an option but should be considered only as a last option, as the natural course of the lesions is to resolve. Antihistamines can alleviate persistent itching.
Prognosis, prevention, and outcomes: Mastocytomas usually appear in infancy, and the occurrence of the lesions resolves by adolescence.
Bibliography
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