Misdiagnosis of capillary malformations in darker skin phototypes

Abstract

In the dermatologic medical literature, there is an underrepresentation of conditions in individuals of color. Due to the lack of representation, it may be harder for clinicians to recognize certain diagnoses in patients with darker skin phototypes leading to misdiagnosis and affecting overall patient management, outcomes, and satisfaction. Here, we present four Black or Indigenous People of Color who were initially referred for hyperpigmentation, hemihyperplasia, or café au lait spots and found to have syndromic capillary malformations.

1. INTRODUCTION

In the medical literature, there is an underrepresentation of conditions in individuals of color.¹ Therefore, it may be harder for clinicians to recognize certain diagnoses in patients with darker skin phototypes, which can lead to misdiagnosis and affect overall patient management, outcomes, and satisfaction. Here, we present four Black or Indigenous and People of Color (BIPOC) individuals with syndromic capillary malformations (CMs) where recognition of the capillary malformation was essential for their diagnosis. All patients provided consent.

2. CASE REPORTS

Patients 1 and 2 are 6- and 11-year-old siblings of Russian, Polish, German, Ashkenazi Jewish, and African ancestry. Their half-brother was referred to genetics for neurofibromatosis evaluation for presumed café au lait macules (CALMs). Patient 1 had small, irregularly shaped, reddish-brown patches on her right infraorbital cheek, right frontal scalp, bilateral legs, and right hand at 14 months of age. At follow-up, she had greater than 20 such patches on the face, trunk, and extremities (Figure 1). Patient 2 was initially referred to genetics for hemihypertrophy of the right upper extremity. At 5 years old, he was noted to have reddish-brown patches on his left nasal ala, philtrum, bilateral legs, right hand, and fourth finger. At follow-up, he had similar patches scattered on his trunk and extremities with hypermobility of the hands and proportionate hypertrophy of his right upper extremity (Figure 2). Genetic testing showed a heterozygous pathogenic variant in RASA1 (c.2026C>T; p. Gln676*) consistent with a diagnosis of CM-AVM. Brain and spine MRI revealed no AVMs.

FIGURE 1.

Patient 1 with reddish-brown and brown patches on leg. One has a halo of lighter skin surrounding

FIGURE 2.

Irregularly shaped, small reddish-brown patches on abdomen of Patient 2

Patient 3 is a 15-year-old African-American girl noted at birth to have vascular birthmarks of her face and presumed CALMs on her trunk and extremities. Physical examination at age 5 years revealed a reddish-brown patch on the forehead and scattered 1.5–4 cm reddish-brown telangiectatic patches scattered on the torso and upper extremities (Figure 3). Dermoscopy of the lesions showed varying features of homogeneous brown pigmentation with subtle telangiectasia, homogeneous brown pigmentation, or a reticular pigment network with more prominent fine telangiectasias. Some of the lesions were observed to have a vasoconstrictive halo around the periphery. Biopsy was read as consistent with CALMs because the telangiectasias were not obvious on the skin sample taken. MR angiography at age 15 years showed an extracranial AVF within the right frontal scalp. Genetic testing revealed a heterozygous pathogenic variant in RASA1 (c.1659C>Asp. Tyr553Term), confirming the diagnosis of CM-AVM.

FIGURE 3.

Brown patch on right arm of patient 3

Patient 4 is a 17-year-old female of African, Jamaican, Native American, and Irish ancestry referred for hemihyperplasia of the left lower extremity and a reddish-brown birthmark of the right lower extremity. Radiographs showed a 1.3 centimeter leg length discrepancy and volumetric analysis revealed a 232 milliliter difference. Dermoscopy of her right leg birthmark showed features of a reticulated capillary malformation rather than hyperpigmentation (Figure 4), consistent with a clinical diagnosis of capillary malformation with undergrowth (CMU) of the right lower extremity rather than hemihyperplasia of the left lower extremity.² Authorization for genetic testing is pending.

FIGURE 4.

Brown patches with irregular borders on right leg. Girth of right leg is smaller than left

3. DISCUSSION

In patients with darker skin phototypes, a high clinical index of suspicion in addition to dermoscopy, blanching the lesion, and examining body surfaces with less melanin such as the palms can help differentiate CMs from pigmented lesions such as CALMs. It is known that the CMs of CM-AVM often exhibit a brown discoloration occurs over time. A study in which the majority of patients were Caucasian (83%) showed that brown discoloration was the most common color change noted within high flow vascular stains (HFVS).³ In another study of patients with Fitzpatrick III skin type, the CMs of CM-AVM appeared pink clinically on all patients though dermoscopy revealed brownish pigmentation.⁴ While this underlying pigmentation may also be seen under dermoscopy in CMs of CM-AVM’s in BIPOC, the skin findings may prove even more clinically subtle. Possible explanations proposed for this pigmentary pattern include an abundance of mast cells⁴ and increased stimulation of melanocytes due to increased blood flow or RAS gene pathway activation.⁵

In our experience, individuals with darker skin phototypes may present with CMs that have been misdiagnosed as CALMs. However, the absence of a vascular pattern under dermoscopy in CALMs can help differentiate the two.⁴ Misdiagnosis may lead to an unnecessary workup for neurofibromatosis or Legius syndrome and omission of the appropriate imaging evaluations for patients with syndromic capillary malformations. In summary, it is essential to report conditions in varying skin phototypes to enhance recognition and improve diagnosis and treatment in BIPOC individuals.