Understanding of vascular lesions or ‘birthmarks’ has been hampered by confusing erroneous terms employed to describe and classify these lesions. An analysis of various scientific articles and newer editions of medical text books revealed that significant confusion prevails among the medical and scientific fraternity over the usage of correct nosology for defining a vascular lesion. Hemangiomas are true benign neoplasms developing after few weeks of birth, characterized by endothelial cell proliferation, and they invariably undergo spontaneous involution by 9 years of age. Vascular malformations are developmental anomalies of vascular plexus that are present from birth, characterized by normal endothelial cell turnover rate, and persists throughout life. The clinical appearances of the vascular lesions are similar and it is often difficult if not impossible to correctly diagnose these lesions. Even after the implementation of International Society for the Study of Vascular Anomalies (ISSVA) classification since 1996, the medical fraternity still persists with the old confusing nomenclatures while diagnosing and reporting vascular lesions. As a clinician and academician it is important to differentiate between the vascular lesions as they show different clinical, pathological, and biological behaviour, thus requiring different management and treatment modalities. In this review the authors advocate the usage of correct nosology for defining specific vascular benign lesions to avoid inaccurate diagnoses and potential mismanagement.
The earliest attempt at classification of vascular lesions was made by Virchow (1863) and Wegner (1877), who gave an anatomo-pathologic classification – (a) angioma, (b) lymphangioma. 1 Later researchers classified the benign vascular lesions (1) according to the type of fluid they contained – (a) hemangioma (blood-containing lesion), (b) lymphangioma (lymph-containing lesion), and (2) according to the size of the vascular channels – (a) capillary (small diameter vascular channels), (b) cavernous (large diameter vascular channels). 2 In 1982, Mulliken and Glowacki published the biological classification based on the endothelial cell characteristics, physical findings, and natural history of the vascular lesion. 3 Mulliken’s classification differentiates vascular lesions with endothelial cell proliferation (hemangioma) from vascular lesions with structural anomalies (vascular malformation). 1-6 In 1996, this classification was adopted by the International Society for the Study of Vascular Anomalies (ISSVA) in their first workshop held in Rome. 4 The society modified the biological classification in their continuing workshops, and presently ISSVA differentiates vascular tumors from vascular malformations based on their history, clinical appearance, imaging and pathological features, and biological behaviour (Table 1). 3-5 The goal of this review is to advocate correct nosology for defining specific vascular benign lesions and to henceforth avoid the usage of out dated confusing nomenclatures by the medical and scientific fraternity that have led to inaccurate diagnoses, research, and mismanagement of these lesions.
Table 1 . Modified International Society for the Study of Vascular Anomalies (ISSVA) 2007 classification
|Vascular Tumor||Vascular Malformation|
Hemangiomas are true benign neoplasms of endothelial cells. 1-6 They are the m ost common benign soft tissue tumor of infancy and childhood, occurring in 12% of all infants. 4-8 They are found in greater frequency in whites, girls, twins, premature infants, and are usually born to mothers of higher maternal age. 1,2,4-8 They occur most frequently in the head and neck region (60%), followed by the trunk (25%) and the extremities (15%). 4-6 ISSVA separates hemangioma into Infantile Hemangiomas (IH) and Congenital Hemangiomas (CH). 4-6
Infantile Hemangiomas ( outdated term - juvenile hemangioma) are not present at birth and arises during the first 8 weeks of life. 1,2,4-7 Initially the lesion clinically appears as an circumscribed area of discoloration or telangiectasia of facial skin. 4-7 It exhibits a high proliferative phase for 6-12 months and grows rapidly into a raised rubbery bright-red tumor (resembling a strawberry, hence outdated term strawberry hemangioma) . 2,4-7
The proliferative phase is followed by a gradual involution phase and a spontaneous regression by the age of 5-9 yr. 4-7 50% of all hemangiomas will completely involute by the age of 5 yr and 90% by the age of 9 yr. 1,2,4-740% of involuted IH may clinically show scaring, wrinkling, telangiectasia, or loose fibro-fatty tissue at the site of their clinical appearance. 1,5 ISSVA categorizes IH depending on site of its occurrence as focal, segmental, and indeterminate, and depending on the depth of the lesion from the skin surface as superficial, deep and mixed . 4,6 Focal IH are the most common variant, appearing as localized raised tumor-like lesion that tends to occur at the area of embryological fusion. 5,6 Segmental IH are flat plaque-like larger lesions that show a geographic segmental distribution, and Indeterminate IH shows characteristics of both focal and segmental IH. 5,6 Colour of the IH varies with the depth of the lesion and they can be bright red (superficial), purple, blue, or normal skin colour (deep). 1,2,5,6