Vascular Lesions: Hemangiomas, Angiokeratoma, Pyogenic Granuloma, Glomus Tumor

01Cherry (senile) angioma is the prototypical adult vascular lesion. Multiple bright-red papules develop on the trunk and extremities from the third decade onward, increasing with age. Dermoscopy shows red or red-blue lacunae arranged across a sharply demarcated lesion, often with white septae separating the lacunae. Larger or older cherry angiomas may thrombose and appear blue-purple to black. The differential against angiokeratoma centers on the absence of a whitish veil and the absence of corkscrew vessels in cherry angioma.

02Angiokeratoma encompasses solitary and multiple variants. Solitary angiokeratoma typically arises on the lower extremity as a dark blue-purple to black papule with hyperkeratotic surface. Dermoscopically, blue-purple lacunae predominate, often partially obscured by an overlying whitish veil corresponding to compact orthokeratotic stratum corneum. Corkscrew vessels (looped, twisted vessels visible at the lesion margin or within thinner regions) are characteristic. Black homogeneous areas correspond to thrombosed vessels. The differential against melanoma is real and important: a thrombosed angiokeratoma may show black homogeneous areas, blue color, and irregular borders, all of which can mimic nodular melanoma. The whitish veil, the corkscrew vessels, and the peripheral lacunae favor angiokeratoma.

03Pyogenic granuloma (lobular capillary hemangioma) presents most often on the face, hands, and oral mucosa as a rapidly growing red papule, often ulcerated, sometimes pedunculated, with a peripheral collarette of scale (the white-yellow rim where the surrounding epidermis grows up around the lesion base). Dermoscopy typically shows a homogeneous red structureless area with peripheral white collarette, sometimes with white intersecting lines (white rail lines) corresponding to collagen strands separating tumor lobules, and frequent ulceration. The history of rapid growth (days to weeks) and frequent bleeding with minor trauma raises the diagnosis. The major differential is amelanotic melanoma, which can also present as a rapidly growing pink-red papule with ulceration; the absence of any pigment criterion in pyogenic granuloma and the youth of typical patients lean toward the benign diagnosis, but in adults excision and histology are routine because the cost of misdiagnosis is high.

04Glomus tumor is a rare benign neoplasm of glomus body (specialized arteriovenous shunt) cells, most often subungual, presenting with the classical triad of severe paroxysmal pain, exquisite cold sensitivity, and pinpoint tenderness on the Love test. Dermoscopically, a subungual blue-purple to red discoloration is visible through the nail plate; longitudinal erythronychia (a single red longitudinal nail band) is a recognized clue. Imaging (ultrasound or MRI) confirms the deep vascular tumor before surgery. Multiple glomus tumors (glomangiomas) occur familially, sometimes associated with the GLMN gene. Outside the nail unit, glomus tumors arise on the digits, palms, soles, and rarely deep soft tissue.

05Spider angioma (nevus araneus) presents as a central pulsating arteriole with radiating telangiectatic legs, classically on the face, neck, and upper trunk. Dermoscopy shows the central red dot with branching small vessels. Multiple lesions in adults raise the differential of liver disease, pregnancy, estrogen therapy, or hyperthyroidism. In children, multiple spider angiomas can be physiologic. The differential is rarely difficult: the central pulsating arteriole and radiating pattern are highly characteristic.

06Infantile hemangioma is the most common vascular tumor of infancy, with a phase of rapid postnatal proliferation followed by spontaneous involution. The spectrum includes superficial (strawberry, bright red), deep (blue, soft, compressible), and mixed lesions. Dermoscopy of superficial lesions shows red and red-blue lacunae arranged in lobules with intervening pale septae (lobular pattern). Involuting lesions develop white scar-like areas, fibrofatty residual changes, and persistent telangiectasia. PHACES syndrome (large facial hemangioma plus posterior fossa malformations, hemangioma, arterial anomalies, cardiac defects, eye abnormalities, and sternal cleft) is the most important syndrome to consider when a large segmental hemangioma is present.

07Lobular capillary hemangioma is the histopathologic name for pyogenic granuloma. The term is preferred in pathology because the lesion is neither pyogenic (not infectious) nor a true granuloma. Histopathology shows lobules of capillaries with intervening fibromyxoid stroma, often with surface ulceration and collarette. Recent literature describes intravascular pyogenic granuloma and disseminated pyogenic granuloma as rare variants.

08Vascular malformations differ from hemangiomas biologically. They are present at birth, grow proportionally with the patient, and never involute spontaneously. Capillary malformations (port-wine stain) appear as flat red-purple patches following dermatomal or unilateral patterns; the GNAQ R183Q mutation drives most cases and the recognition has clinical implications (Sturge-Weber syndrome screening with brain MRI in V1 distribution port-wine stains). Venous malformations appear as soft compressible blue lesions; lymphatic malformations show clear or hemorrhagic vesicles (lymphangioma circumscriptum) with characteristic frog-spawn appearance. Arteriovenous malformations are pulsatile, warm, and have a rapid filling pattern. Dermoscopy of capillary malformations shows uniform red coloration with a pebble-like or globular pattern.

09Glomeruloid hemangioma is a rare hemangioma morphologically distinct because of intravascular capillary tufts resembling glomeruli; it is characteristically associated with POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes). Recognition of multiple glomeruloid hemangiomas should prompt POEMS screening with serum protein electrophoresis and skeletal survey for sclerotic bone lesions.

10The dermoscopic differential against amelanotic melanoma is the most clinically important. Milky-red areas, polymorphic vessels (multiple morphologies in one lesion), and white shiny structures are the melanoma cues that should not appear in benign vascular lesions. Pyogenic granuloma is the single most common amelanotic melanoma mimic in routine practice, and adult-onset rapidly growing red papules should be excised, not monitored, even when pyogenic granuloma is the leading diagnosis. Kaposi sarcoma presents as red-purple to brown macules, plaques, or nodules, often on the lower extremities or in HIV-positive patients on the face; dermoscopy shows the rainbow pattern (multiple colors radiating across the lesion under polarized light) plus polymorphic vascular structures. Angiosarcoma in elderly patients on the scalp and face shows ill-defined erythematous to bruise-like patches that progress to nodules and ulceration; dermoscopy is often non-specific (red-purple structureless areas, white shiny streaks, polymorphic vessels), and any ill-defined bruise on the scalp of an elderly patient deserves biopsy.