Hemoporphyrin Photodynamic Therapy for a Case of Unilateral Nevoid Telangiectasia
Unilateral nevoid telangiectasia (UNT) is a rare cutaneous vascular disorder characterized by superficial telangiectasia distributed in a unilateral, linear pattern. The condition can be either congenital or acquired, and its pathogenesis remains unclear. While most scholars believe that hyperestrogenic states play a significant role in UNT, the exact mechanisms are not fully understood. Pulsed-dye laser (PDL) therapy has been the mainstream treatment option for UNT. However, this case report presents a successful alternative treatment for PDL-resistant UNT using hemoporphyrin-mediated photodynamic therapy (HMME-PDT).
The case involves an 8-year-old boy with a 4-year history of progressive asymptomatic erythema. Initially, the lesion was fingertip-sized and localized to the extensor aspect of the left lower leg. Over time, it gradually enlarged and spread to the entire left lower extremity. The lesion blanched completely upon diascopy, a characteristic feature of UNT. The patient had undergone two sessions of 585 nm PDL therapy, but no significant improvement was observed. The patient had no medical history of hepatic disease or other systemic conditions. A general physical examination was unremarkable, but dermatological examination revealed generalized telangiectasia in a linear distribution along the left lower extremity, left buttock, and left back.
Laboratory tests, including blood routine examination, liver and renal function tests, blood coagulation tests, and sexual hormone levels, revealed no abnormalities. Dermatoscopy showed branched vessels with a reddish background, further supporting the diagnosis of UNT. A skin biopsy from the left leg revealed normal epidermis and dilated capillaries with minimal erythrocyte exosmosis in the superficial dermis. Immunohistochemical staining showed that the deformed vessel walls were positive for vascular endothelial growth factor (VEGF) but negative for podoplanin (D2-40), glucose transporter-1 (Glut-1), and estrogen receptor/progesterone receptor (ER/PR).
Based on these findings, a definitive diagnosis of UNT was made. After obtaining informed consent from the patient’s parents, HMME-PDT was initiated as a treatment modality. The treatment involved intravenous infusion of HMME (5 mg/kg) followed by irradiation with 532 nm LED green light equipment for 20 minutes. The power density was set at 90 mW/cm². Two irradiation spots were used: a larger spot (10 cm in diameter) above the left shank and a smaller spot (4.5 cm in diameter) above the left thigh. Significant improvement in the lesions was observed after three months of follow-up.
During the second treatment session, the patient’s parents requested an enlargement of the exposure area to reduce treatment costs. After obtaining informed consent, two sets of equipment were used for irradiation under close clinical monitoring. Following the second session, more than 85% of the lesions were removed, with only slight local skin hyperpigmentation remaining. No abnormalities were detected in blood routine examination, coagulation parameters, or liver and renal function during follow-up. Dermatoscopy revealed a significant reduction in dilated blood vessels, and no adverse reactions or recurrence were observed within 14 months of follow-up.
The role of estrogen in the pathogenesis of UNT remains controversial, as several patients with UNT have shown normal estrogen and progesterone levels, and the absence of ER/PR in the skin. The predilection sites for UNT are typically the C3–C4 and trigeminal nerve dermatomes, with only about a dozen reported cases involving the lower limbs. The main clinical differential diagnoses for UNT include telangiectasia macularis eruptiva perstans (TMEP), angioma serpiginosum (AS), and port-wine stains (PWS). TMEP can be distinguished by an increased number of mast cells in the superficial dermis, while AS is characterized by multiple oval red lagoons under dermoscopy and does not blanch upon diascopy. PWS, on the other hand, typically appears at birth and gradually deepens in color and thickness over time, with dilated vessels extending into the lower dermis and subcutaneous tissue.
In cases of UNT associated with high estrogen levels, the telangiectasia may fade when estrogen levels normalize. However, in most cases without hormonal abnormalities, symptomatic treatment is sufficient for cosmetic improvement. PDL has been widely used to treat UNT, as the yellow light (585 or 595 nm) produced by PDL is absorbed by hemoglobin, causing photocoagulation and blanching of the lesions. However, PDL has several limitations, including competitive absorption of epidermal melanin, limited effectiveness for vessels larger than 150 µm in diameter, and poor response to reticulated blood vessels. Previous studies have reported only moderate improvement in UNT patients after PDL treatment, with evidence of recurrence in some cases.
In 2016, HMME-PDT was approved in China for the treatment of PWS, particularly in cases resistant to PDL. PDT works by producing cytotoxic singlet oxygen through the interaction of light, photosensitizers, and oxygen, leading to endothelial damage, thrombosis, and vascular occlusion. Compared to PDL, PDT can target dilated vessels of any size and penetrate deeper into the tissue. Additionally, PDT can destroy dilated vasculature through both photochemical and photothermal reactions, whereas PDL relies solely on photothermolysis. The normal epidermis and dermal tissues are spared from damage due to the low concentration of photosensitizer in these tissues, while endothelial cells accumulate higher concentrations of the photosensitizer.
Both UNT and PWS are superficial capillary malformations, and VEGF has been implicated in the pathogenesis of both conditions. HMME-PDT has been shown to decrease the expression of VEGF in human vascular endothelial cells, thereby reducing vascular expansion and proliferation. Based on the similarities between UNT and PWS, HMME-PDT was attempted in this case and demonstrated excellent efficacy. However, HMME-PDT has its limitations, including the need for patients to avoid strong sunlight exposure for two weeks post-treatment and the requirement for multiple sessions in cases with extensive lesions.
In conclusion, HMME-PDT represents a promising treatment modality for UNT, particularly in cases resistant to PDL. Its effectiveness and safety make it a viable option for patients seeking cosmetic improvement. However, further studies with larger sample sizes are needed to confirm these findings and establish HMME-PDT as a standard treatment for UNT.
doi.org/10.1097/CM9.0000000000001335
Was this helpful?
0 / 0