Lymphangioma Circumscriptum (Lymphangiectasia, Dermal Lymphangioma)

Are You Confident of the Diagnosis?

What to be alert for in the history

A rare condition, lymphangioma circumscriptum (LC) has been divided into two broad categories, each with its own typical presentation and history. These two categories are classical and localized. In the classical form, the condition’s hallmark vesicles are typically present at birth or develop shortly thereafter. For lesions of either type developing after birth, the patient might provide a history of localized swelling or edema prior to the eruption of vesicles at the same site.

Classical LC has a predilection for appearing in the proximal limbs, axilla, buttocks, trunk and tongue. The clustered vesicles characteristically cover a surface area greater than a square centimeter, and it is uncommon for vesicular areas to form plaques or undergo verrucous changes.

The localized type is less confined by age at presentation or body distribution. The vesicles can appear at any age, and 25% of patients are greater than 45 years old at first presentation. Localized type characteristically covers a surface area of less than a square centimeter and may form thick plaques or undergo verrucous changes.

Unlike its classical counterpart, localized type can appear nearly anywhere on the body. Despite classical LC’s affinity for certain body regions, both types have been described appearing in the oral cavity, on the penis, vulva and scrotum, and even within the peritoneum, mesentery and bone.

Though LC is often asymptomatic, vesicles are prone to rupture with weeping and crusting, and a history of recurrent bacterial infection is common. This is particularly true if the lesions are itchy or irritating, as excoriations allow a portal for bacterial entry. Though the clustered vesicles may be painful, they should not undergo rapid change or growth. Any such history should raise suspicion of other conditions.

Characteristic findings on physical examination

On clinical examination, LC is best described as clustered thin-walled and translucent vesicles, most often less than 5mm in diameter. The vesicles contain clear lymphatic fluid, though hemorrhage can tint the fluid pink, red, brown or black. Their clustered appearance on smooth skin often draws comparisons to frog spawn (Figure 1). The vesicles may slowly grow larger and rupture, leading to crusting, weeping or bleeding, and thick, hyperkeratotic plaques with a verrucous appearance may form in adjacent skin. Localized swelling is often palpable surrounding the lesions.

Figure 1.

Dermatoscopic inspection demonstrates septated lacunae filled with clear fluid that can be tinted pink, red, brown or black by the presence of erythrocytes. If there is extensive hemorrhage into the lymphatic channels, the brilliant red appearance of fresh blood can make LC indistinguishable from a hemangioma under the lens of a dermatoscope.

Diagnosis confirmation

The rarity, varying appearance and distribution of LC can make for a challenging differential diagnosis, which includes the following:

– Cutaneous metastases of internal malignancy (particularly carcinoma telangiectoides). Malignancy is typically associated with a history of cancer near the site of cutaneous involvement, unexpected weight loss, or a family history of cancer. Biopsy of the lesion can identify malignant proliferation.

– Lymphangiosarcoma, a malignant neoplasm derived from lymphatic tissue and rarely arising from LC itself, can be distinguished from LC by biopsy.

– Lymphangiectasias: These have the same clinical appearance but are derived from obstructed normal lymphatic channels and can be distinguished by their appearance at sites of trauma, surgical incision or radiation therapy.

– Hemangioma: May have identical appearance under a dermatoscope, but a biopsy can distinguish the two.

– Warts: LC may undergo verrucous plaque formation making clinical appearance similar, particularly in the genital region, but tissue biopsy can delineate between the two entities.

– Molluscum contagiosum: LC can appear in the genital region with an appearance similar to molluscum, but again, biopsy will establish the diagnosis.

– Angiokeratoma (identified on biopsy).

Expected results of diagnostic studies

Obviously, tissue sample and histologic examination are critical to establishing diagnosis and treatment modalities. Under the microscope, numerous dilated lymphatic channels are observed in the papillary dermis underlying a thinned epidermis, though hyperkeratosis or acanthosis may be noted superficial to the lymphatics. The channels typically extend to the reticular dermis or subcutaneous tissue where they branch from deep smooth muscle-lines lymphatic cisterns of larger diameter.

The lymphatic spaces may contain varying numbers of red or white cells, depending on the degree of hemorrhage into them. Capillary tufts may be present within the tissue sample (Figure 2, Figure 3).

Figure 2.

Figure 3.

While imaging does not share a role in establishing the diagnosis of LC, magnetic resonance imaging (MRI) does have utility in planning treatment. Effective surgical treatment of LC necessitates excision of the deep lymphatic cisterns, which feed the surface vesicles. MRI can demonstrate the location and extent of these often deeply subcutaneous structures and allow for the construction of well-informed surgical margins.

Who is at Risk for Developing this Disease?

Though the most common of the cutaneous lymphangiomas, LC is rare. Well constructed epidemiologic studies determining the incidence of LC do not appear to exist, but lymphatic malformations occur in approximately 1.2 to 2.8 of every 1,000 live births in the United States. LC represents only a small percentage of these cases; 90% of patients who will get LC have it by the age of 2 years, and half of these individuals will have been born with the condition.

Despite these numbers, LC can appear in a patient of any age, even into late adulthood. Studies have not revealed any patterns of familial transmission, but more research into the epidemiology of this uncommon condition is needed. No specific risk factors for developing LC have been identified.

What is the Cause of the Disease?

Etiology

Pathophysiology

Despite its superficial manifestations, LC is a problem of abnormal lymphatic vessels in the deep subcutaneous tissues. There, large dilated and abnormal lymphatic cisterns branch smaller channels that travel upward through the skin to blind endings in the papillary dermis.

These cisterns and their aberrant channels form a closed, fluid-filled system that does not communicate with normal lymphatics in the region. The deep cisterns have thick walls lined by smooth muscle fibers that contract, transmitting fluid pressure to the superficial channels. The increasing pressure dilates the superficial channels, which eventually protrude through the skin forming the typical thin-walled vesicles. Excision without removing the deep cisterns will result in recurrence, as the cisterns will sprout and feed new superficial channels.

The origin of the deep lymphatic cisterns is not known, but many propose they are an isolated remnant of primitive embryonic lymph sacs. During normal development, these sacs, which most commonly form at the site of limb buds, grow to confluence forming the normal lymphatic channels responsible for recirculating interstitial fluid. Failure to merge with the rest of the early lymphatic system may cause one of these sacs to form an isolated cistern and its closed system of channels leading to LC. The location of primitive lymph sac development at sites of limb buds would account for classical LC’s preferential presentation at the proximal limbs.

Systemic Implications and Complications

The most common complications for LC are bleeding and recurrent bacterial infection. Staphylococcus aureus is the most common causative organism of infection and can be treated with oral antibiotics. LC has been reported to occasionally occur concurrently with other lymphatic malformations such as cystic hygroma or cavernous lymphangioma, and these conditions can be detected with routine physical examination.

Case reports exist describing rare progression to certain malignancies, including Dabska tumors, squamous cell carcinoma and lymphangiosarcoma. Lymphangiosarcoma has been most commonly reported as arising from LC following radiation therapy. Lymphangioma circumscriptum, or the site of surgical excision of LC, should be observed by a physician for any rapid change or growth. Biopsy should be performed if any suspicion of malignancy arises. Radiation therapy is never recommended as a treatment for LC to minimize any risk of progression to lymphangiosarcoma

Treatment Options

Treatment options for LC are summarized in Table I.