They can also be raised and elevated from the skin, forming papules and confluent bright-red plaques like raised islands. Infantile hemangiomas have historically been referred to “strawberry marks" or "strawberry hemangiomas” in the past, as raised superficial hemangiomas can look like the side of a strawberry without seeds, and this remains a common lay term.Superficial IHs in certain locations, such as the posterior scalp, neck folds, and groin/perianal areas, are at potential risk of ulceration. Ulcerated hemangiomas can present as black crusted papules or plaques, or painful erosions or ulcers. Ulcerations are prone to secondary bacterial infections, which can present with yellow crusting, drainage, pain, or odor. Ulcerations are also at risk for bleeding, particularly deep lesions or in areas of friction. Multiple superficial hemangiomas, more than five, can be associated with extracutaneous hemangiomas, the most common being a liver (hepatic) hemangioma, and these infants warrant ultrasound examination.Deep IHs present as poorly defined, bluish macules that can proliferate into papules, nodules, or larger tumors. Proliferating lesions are often compressible, but fairly firm. Many deep hemangiomas may have a few superficial capillaries visible evident over the primary deep component or surrounding venous prominence. Deep hemangiomas have a tendency to develop a little later than superficial hemangiomas, and may have longer and later proliferative phases, as well. Deep hemangiomas rarely ulcerate, but can cause issues depending on their location, size, and growth. Deep hemangiomas near sensitive structures can cause compression of softer surrounding structures during the proliferative phase, such as the external ear canal and the eyelid.
In 2002, Svenssons group generated a COMP-null mouse to study the COMP protein in vivo. These mice showed no anatomical, histological, or even ultrastructural abnormalities and none of the clinical signs of PSACH or MED. Lack of COMP was not compensated for by any other protein in the thrombospondin family. This study confirmed that the disease is not caused by reduced expression of COMP.In 2007, Piròg-Garcias group generated another mouse model carrying a mutation previously found in a human patient. With this new model, they were able to demonstrate that reduced cell proliferation and increased apoptosis are significant pathological mechanisms involved in MED and PSACH. In 2010, this mouse model allowed a new insight into myopathy and tendinopathy, which are often associated with PSACH and MED. These patients show increased skeletal muscle stress, as indicated by the increase in myofibers with central nuclei. Myopathy in the mutant mouse results from underlying tendinopathy, because the transmission of forces is altered from the normal state. There is a higher proportion of larger diameter fibrils of collagen, but the cross-sectional area of whole mutant tendons was also significantly less than that of the wild-type tendons causing joint laxity and stiffness, easy tiring and weakness. This study is important because those diseases are often mistaken for neurological problems, since the doctor can detect a muscle weakness. This includes many painful and useless clinical neurological examination before the correct diagnosis.