More than 90% of cases of juvenile myofibromatosis have onset in infancy, although the disorder can first present later in childhood or less often in adults. The tumors can continue to develop throughout an individual’s life.
The specific symptoms of infantile myofibromatosis are broad, and the severity can vary. Some infants have mild disease that resolves on its own without treatment (spontaneous regression). Others develop extensive disease that involves internal organs and can cause life-threatening complications if left untreated. Therefore, it is important to note that affected individuals may not have all of the symptoms discussed below and that every individual case is unique. Parents should talk to their child’s physician and medical team about their specific case, associated symptoms and overall prognosis.
The tumors or Lesions that characterize infantile myofibromatosis are usually seen as firm, flesh or purple covered Bumps (nodules) on the skin or just underneath the top layer of the skin (subcutaneous layer). These superficial Lesions may be freely movable; deeper Lesions are generally immobile. Skin Lesions may be crusted or hardened (indurated). The Lesions are usually not painful or tender. The overlying skin may be discolored red or purple and ulcerated. Lesions are also commonly found in muscle, soft tissue and bone, and very rarely the internal organs.
Although the tumors that characterize infantile myofibromatosis do not spread (metastasize), they can grow large enough to damage or compress nearby structures in the body. Pain, which occurs when tumors press against adjacent nerves, can develop. In some cases, tumor growth can also cause bone destruction, disfigurement, and even physical limitations.
Infantile myofibromatosis is sometimes broken down into separate types, specifically solitary, multicentric, and multicentric with visceral involvement.
The solitary form is most common, accounting for approximately 75% of cases of infantile myofibromatosis. This form occurs predominantly in males and is characterized by one nodule or lesion that most commonly occurs in the skin, often extending into subcutaneous tissue and/or muscle tissue. The nodule is usually found in the head, neck or trunk areas. A solitary nodule of the bone can also occur, but is extremely rare.
The multicentric forms are more common in females. The multicentric form without visceral involvement is characterized by multiple Nodules that can arise in different areas of the skin, subcutaneous tissue or muscle. The multicentric form with visceral involvement is the most severe form of the disorder and is characterized by multiple growths of the skin, muscles, and bones along with the involvement of the internal organs such as the lungs, heart, and gastrointestinal tract. In some cases, only one organ may be involved; in other cases visceral involvement is widespread. This form of infantile myofibromatosis can cause severe, life-threatening complications depending upon the exact location of the lesion and the specific organs involved.