2014 October Dermatology Clinic
A white male, aged 5 years, presents to the dermatology clinic for diagnosis and management of a lesion on his thigh. His mother reports the lesion began 5 months ago as a small plaque, with subsequent enlargement and development of fluid-filled lesions at the skin surface.
The lesions are asymptomatic but bleed with minor trauma. The boy has no other medical issues and does not take any medications.
His social history is noncontributory. Physical examination is notable for a 13-cm plaque with overlying yellow and hemorrhagic fluid-filled vesicles with a “frog-spawn” appearance.
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Microcystic lymphatic malformations, formerly known as lymphangioma circumscriptum, are congenital malformations of the superficial lymphatic system.1 They are the most common type of lymphatic malformations, which are the result of hyperplasia of the lymphatic network.2 These malformations can be microcystic, macrocystic, or combined.2
There may be superficial involvement of only skin and mucous membranes, deep involvement of areas such as the muscle or bone, or even visceral involvement of sites such as the lung and mediastinum.2 Visceral involvement is relatively rare and seen in only approximately 10% of patients.2
By definition, these congenital malformations are present at birth, but the onset of their clinical manifestation may be delayed by years. Lymphatic malformations are rare overall but are reported to account for 4% of all vascular “tumors” and approximately 25% of benign vascular “tumors” in children.3
No racial predilection for lymphatic malformations has been reported.3 There is conflicting evidence as to whether or not this condition occurs more often in boys or girls, with some studies reporting equal incidence in both genders and others reporting a more frequent incidence in boys.3
In 50% of patients, lymphatic malformations are present at birth.3 Even if clinical manifestations are delayed, the vast majority of patients have characteristic clinical findings by age 5 years.3
Microcystic lymphatic malformations can occur on the skin or in the mouth.2 In the mouth, these lesions may be found on the buccal mucosa, lips, tongue, or oral floor.2 Overall, however, they are located most commonly on the abdomen, axillae, genitalia, tongue, and proximal limbs.1,2
The diagnosis is often made on clinical grounds alone due to the characteristic appearance of these lymphatic malformations. Clinically, microcystic lymphatic malformations are characterized by plaques with crops of clear or hemorrhagic vesicles scattered or clustered on their surface.3
The lesions are usually yellowish but may be pink, red, or dark (purple or black), and they have been described as having a “frog-spawn appearance.”1 When the papules are punctured, they exude clear, colorless lymph.1 At times, microcystic lymphatic malformations may have a verrucous-like surface with a brownish color.1
On the scrotum, multifocal lymphatic malformations, so-called because they are discrete lesions that are not necessarily seen in a localized plaque, may present as clear, thick-walled, vesicle-like lesions.1
If the diagnosis is in question, a skin biopsy is indicated. On biopsy, microcystic lymphatic malformations are characterized by enlarged, distorted, irregular lymphatic channels with varying numbers of smooth muscle cells in their walls and endothelium that is very thin and sometimes barely visible.2
The presence of valves is a specific feature of lymphatic vessels that helps distinguish microcystic lymphatic malformations from other vascular entities, such as angiokeratomas. The lymphatic vessels are usually separated by fibrous septa.2 The epidermis may or may not be hyperkeratotic.2 The lymphatic channels may appear to be empty or to contain watery fluid; hemorrhage may also be seen.2
Congenital lymphatic malformations may be mimicked by acquired cutaneous lymphangiectasia, also known as acquired lymphangiomas. With acquired lymphangiomas, numerous fluid-filled vesicles develop in the background of chronic lymphedematous areas.4
Acquired lymphangiectasias can be seen in the settings of inflammatory conditions (e.g., Crohn disease, morphea profunda, systemic sclerosis), infectious diseases (e.g., tuberculosis, recurrent erysipelas, or cellulitis), and intralymphatic metastases from underlying malignancies.2
Acquired lymphangiomas have also been well-documented to occur after surgical resection, lymphadenectomy, and/or radiotherapy for cancer.2 Less commonly, cutaneous lymphangiectasias have been reported after amputations, corticosteroid-induced atrophy, penicillamine-induced dermopathy, and pregnancy.2 They have also been documented in rare cases in patients with cirrhotic ascites and porphyrias and on the genitalia of the elderly.2
Given the characteristic clinical findings of microcystic lymphatic malformations, there is rarely a differential diagnosis. With very limited cutaneous involvement manifested by only a few grouped vesicles, the diagnosis of a herpes simplex viral infection might be considered. However, in herpetic infections, the grouped vesicles are seen on an erythematous base, which is typically absent in microcystic lymphatic malformations.
Also, the vesicles of lymphatic malformations are generally more persistent, whereas herpes infections are self-limiting. When the vesicles of microcystic lymphatic malformations are hemorrhagic, the differential diagnosis can include angiokeratomas.
Close examination of the lymphatic malformation will generally reveal at least a few clear vesicles suggestive of a lymphatic origin. Having a more verrucous surface, microcystic lymphatic malformations may be mistaken for epidermal nevi. There have also been case reports of both congenital and acquired cutaneous lymphangiomas that resemble condyloma acuminatum.5
There is no standard of care for microcystic lymphatic malformations. Some clinicians favor surgical excision as the treatment of choice for these lesions.2 Following excision, direct closure can be applied for small lesions, but large lesions may require skin grafts or tissue expanders.2
However, many clinicians now favor referral to interventional radiology for sclerotherapy because of concerns regarding cosmetic and functional consequences after extensive surgery as well as the risk of recurrence when the extent of lymphatic malformations are underestimated.2
To prevent recurrences, imaging studies such as magnetic resonance imaging (MRI) are often performed to determine the full extent of the malformation prior to treatment.1 Successful treatment of microcystic lymphatic malformations has also been reported with laser therapy (e.g., carbon dioxide, surface application or intralesional bare fiber, neodymium-doped yttrium aluminum garnet [Nd:Yag], diode, pulsed dye laser, and intense pulsed light).1,2,6
Patients undergoing treatment of genital lymphangiomas should be counseled on the possibility of keloid formation, which has been reported after laser vaporization.1 There are also case reports of successful treatment with radiofrequency ablation, cryoablation, and electrodesiccation.1,2 Patients with microcystic lymphatic malformations of the mouth should be advised on careful dental hygiene.2
Patients who do not wish to undergo treatment but are troubled by transient inflammatory swelling can be treated symptomatically with nonsteroidal anti-inflammatory drugs, corticosteroids, antibiotics, or a combination of these.2
Because our patient had problematic lymphatic drainage with minor trauma, he was referred to interventional radiology for evaluation for possible sclerotherapy. Interventional radiology plans to evaluate the malformation using MRI in anticipation of treatment.
Audrey Chan, MD, is a pediatric dermatology fellow at Texas Children’s Hospital in Houston.
- James WD, Berger T, Elston D. Andrews’ Diseases of the Skin: Clinical Dermatology. 11th ed. Philadelphia, Pa.: Elsevier; 2011:579-580.
- Bolognia JL, Jorizzo JL, Rapini RP, eds. Dermatology. 3rd ed. St. Louis, Mo.: Mosby Elsevier; 2011: Chap.104.
- Schwartz RA. Lymphangioma. Medscape website. emedicine.medscape.com/article/1086806. Updated May 20, 2014.
- Schwartz RA. Lymphangiectasia. Medscape website. emedicine.medscape.com/article/1086917. Updated September 20, 2013.
- Sah SP, Yadav R, Rani S. Lymphangioma circumscriptum of the vulva mimicking genital wart: a case report and review of literature. J Obstet Gynaecol. 2001;27(5):293-296.
- Wang LC, Krunic AL, Medenica MM, et al. Treatment of hemorrhagic lymphatic malformation of the tongue with a pulsed-dye laser. J Am Acad Dermatol. 2005;52(6):1088-1090.
All electronic documents accessed on October 1, 2014