Dermal and Subcutaneous Growths

Definition

An angioma is a common benign vascular growth in older adults. It is also referred to as cherry angioma because of its bright red color ( Fig 7.1A ).

Incidence

Angioma are very common and increase in number as one ages. Virtually all elderly individuals have angioma.

History

Angioma are frequently an incidental finding on the skin examination. They are asymptomatic unless traumatized. Occasionally, the patient or physician is concerned that an angioma may be a melanoma if deep purple color ( Fig 7.2 ).

Physical Examination

Angioma are easily recognized by their smooth surface and red color. There may be few to numerous angiomas occurring most commonly on the trunk but can be on the head and extremities. They vary from being pinpoint macules resembling petechiae to papules or small plaques. Angiomas usually are bright red but may be shades of deep red to purple.

Differential Diagnosis

Angioma is easily recognized most of the time. Petechiae are sometimes confused with numerous small flat angiomas. The occurrence on the trunk and presence for years in a healthy individual makes angioma the diagnosis. When deep purple, a blue nevus or melanoma should be considered. Examination with the dermatoscope is very helpful in visualizing the vascular globules seen in an angioma. If uncertain, a biopsy should be performed.

Laboratory and Biopsy

The diagnosis of angioma is almost always made clinically. If in doubt, a biopsy reveals a well-demarcated collection of small blood vessels in the dermis ( Fig 7.1B ).

Therapy

In most cases, no therapy is needed. If irritated or cosmetically unattractive, they can be shaved off, electrodesiccated, or lasered.

Course and Complications

The number of angiomas increase with age. They are usually of no concern other than for their cosmetic appearance. They are chronic and not associated with complications other than bleeding if traumatized.

Definition

A dermatofibroma is an area of focal dermal fibrosis, often accompanied by overlying epidermal thickening and hyperpigmentation. It appears clinically as a brown papule or small nodule, often more indurated than elevated. The origin is unknown. However, it is probably a response to trauma.

Incidence

Dermatofibromas are common and are often found incidentally during cutaneous examinations. Occasionally, they cause a patient to seek medical advice. They are seen most often in young adults.

History

Dermatofibromas usually are asymptomatic. The patienťs concern, if any, is over the possibility of malignancy.

Physical Examination

Typical dermatofibromas are approximately 5 mm in size and are slightly elevated. They vary in color from light tan to dark brown. The fibrotic nature of the lesion is best appreciated by palpation, which reveals a firm consistency. A helpful diagnostic test is the “dimple sign,” in which pinching results in central dimpling ( Fig. 7.3A ). Most dermatofibromas exhibit this sign; it is rarely seen with any other skin lesion. Dermatofibromas may occur anywhere, but the thighs and legs are the most common locations. One or several lesions may be present.

Differential Diagnosis

With its brown color, a dermatofibroma may be confused with a nevus . Nevi, however, are usually softer and do not exhibit the dimple sign. Darker dermatofibromas may raise a clinical suspicion of melanoma . Dermatofibromas are usually purely brown (a benign color), whereas a nodular melanoma usually has shades of dark gray or blue. If any doubt exists, however, a biopsy should be performed.

Dermatofibrosarcoma protuberans is a low-grade malignant fibrous tumor that grows slowly but persistently, and rarely metastasizes. It is a rare tumor and is distinguished clinically from a dermatofibroma by its larger size, irregular shape, and continued growth.

Laboratory and Biopsy

The diagnosis is usually made clinically. If any doubt exists, a biopsy should be performed to rule out malignancy. The histologic picture is diagnostic and shows a focal proliferation of densely packed collagen bands that are twisting and intertwining ( Fig. 7.3B ). Fibroblasts are interspersed and increased in number. Increased pigmentation of the slightly thickened overlying epidermis accounts for the frequently brown color of these lesions.

Therapy

Therapy is usually not indicated. If desired, a simple excision is sufficient for removal and histologic examination.

Course and Complications

Dermatofibromas are chronic and usually stable in size. They are not associated with any complications.

Pathogenesis

Although the origin is unknown, trauma (e.g., an insect bite) may be an initiating factor for some of these lesions. The proliferation of fibroblasts and subsequent fibrosis may represent an exuberant healing response to injury. However, most patients do not recollect a history of trauma in the area.

Two other lesions are considered within the spectrum of a dermatofibroma. A histiocytoma (an aggregate of histiocytes in a focal area within the dermis) probably represents an early phase in the formation of a dermatofibroma. A sclerosing hemangioma , as the name suggests, shows more of a vascular component, but the end result is that of dermal fibrosis as well.

Definition

An epidermal inclusion cyst ( Fig. 7.4A ) is derived from the upper portion (infundibulum) of the epithelial lining of a hair follicle and is located in the mid and lower dermis. It is also called an epidermoid cyst. Clinically, it appears as a flesh-colored, firm, but often malleable, solitary nodule in the skin.

Incidence

These lesions are common, but usually are not brought to the attention of a physician, so the exact incidence is not known. They may occur at any age.

History

Epidermal inclusion cysts are usually asymptomatic, slow growing, and most frequently are found incidentally by either the patient or the examining physician. Occasionally, they are the primary complaint in a patient concerned about the possibility of malignancy. Another reason for medical attention is rupture of the cyst or secondary infection, either of which produces inflammation, pain, and drainage of foul-smelling material.

Physical Examination

Characteristically, the lesion is a flesh-colored, dome-shaped nodule that feels firm (but not hard). On palpation, it often feels slightly malleable, a finding that suggests the contents are semi-solid. This is a helpful diagnostic aid, as is the finding of a central pore , which represents the opening of the follicle from which the cyst originated. Lesions range in size from 0.5 to 5 cm. They may be located anywhere, but occur most frequently on the head and trunk. If the central pore is patent, the diagnosis is sometimes confirmed by squeezing the lesion and expressing some of the whitish, cheesy, foul-smelling material that is trapped within. This material represents macerated keratin.

Differential Diagnosis

Pilar (trichilemmal) cysts arise from the middle third (isthmus) of the follicular canal. They occur most frequently on the scalp, where they are the most common type of cyst. In other locations, they are less common than epidermal inclusion cysts, but the two may be indistinguishable clinically, and histologically, some cysts may have elements of both. The difference is not critical: both are benign. A lipoma is usually deeper than an epidermal inclusion cyst, and although a lipoma may feel rubbery, it is usually not malleable. When the diagnosis is uncertain, particularly if the lesion feels firm, a malignant tumor must be considered.

Laboratory and Biopsy

Usually, the diagnosis can be made clinically. If desired, confirmation can be obtained by incising and draining the lesion, which reveals the cheesy, foul-smelling, keratinous contents. A biopsy is equally confirmatory, but usually not necessary ( Fig. 7.4B ).

Therapy

Frequently, no therapy is requested or needed. If removal is desired, the entire cyst should be excised with its lining, to prevent recurrence. This is accomplished by incising the skin overlying the cyst without disrupting the cyst wall and then bluntly dissecting the entire cyst, along with its wall. If the cyst breaks, a curette can be used to remove the remaining contents and cyst wall. Elliptical excision is usually required for removal of cysts that have previously ruptured and scarred.

Course and Complications

Untreated, most epidermal inclusion cysts reach a stable size, often in the range of 1 to 3 cm, rarely larger.

Complications are rare and usually limited to occasional rupture or infection. Rupture or infection results in redness and tenderness of the cyst and, on examination, increased fluctuance. If this occurs, the lesion should be treated as an abscess with incision and drainage, and occasionally oral antibiotics.

Multiple epidermal inclusion cysts are a feature of Gardner syndrome , an uncommon, autosomal-dominant, heritable disorder manifested by multiple epidermal cysts, fibromas, osteomas, and intestinal polyps. The intestinal polyps often undergo malignant degeneration.

Pathogenesis

Epidermal inclusion cysts arise from the upper portion (infundibulum) of a hair follicle. The epidermal lining of the cyst is identical to that of the surface epidermis and produces keratin, which, having no place to shed, accumulates and forms the cystic mass.

Definition

An infantile hemangioma ( Fig. 7.5A ) is a benign proliferation of blood vessels in the dermis and subcutis. The vascularity imparts a red, blue, or purple color to these lesions, depending on the size and depth of the proliferative vessels.

Incidence

Infantile hemangiomas are the most common soft tissue tumor of infancy, occurring more frequently in females, premature, and Caucasian infants. They are likely to be brought to the attention of a physician because of their rapid growth or cosmetic concerns.

History

Most arise in the first few weeks of infancy. Infantile hemangiomas are usually asymptomatic, except when they ulcerate, or cause local obstruction – fortunately an uncommon occurrence.

Physical Examination

Superficial infantile hemangiomas have a bright red color, whereas the deeper subcutaneous forms have a bluish hue. Mixed infantile hemangiomas are bright red, dome-shaped nodules.

Differential Diagnosis

In contrast, vascular malformations (port-wine stain, lymphangioma circumscriptum, venous malformation) are generally present at birth and do not regress spontaneously. Rapidly involuting congenital hemangioma (RICH) is present at birth, rapidly involutes by 1 to 2 years, and is Glut-1 negative on biopsy. Noninvoluting congenital hemangioma (NICH), which is present at birth, has superficial telangiectasia, gradually enlarges as one ages, is Glut-1 negative, and usually requires surgery.

Laboratory and Biopsy

A biopsy, if done, reveals a marked increase in the number of blood vessels, many of which are dilated ( Fig. 7.5B ). An infantile hemangioma has glucose transporter molecule, Glut-1, positive staining.

Therapy

Observation is the most appropriate therapy for many infantile hemangiomas. Although these lesions grow over the first year of life (and during this time, the parents will need repeated reassurance), they usually involute spontaneously over the ensuing years with a good cosmetic result. For ulcerating, large, head and neck or groin infantile hemangiomas, therapeutic intervention may be necessary as vision, respiration, or a good cosmetic result may be compromised.

Therapeutic options include systemic propranolol as the first line of therapy, topical timolol, intralesional and potent topical steroids, pulsed-dye laser, and surgical excision.