Phenotypic association of presence of a somatic GNAQ mutation with port-wine stain distribution in capillary malformation

Sporadic hypertrophic and nodular port-wine stain: a study of 27 cases with emphasis on histological features and novel mutation type

AIMS

To investigate the clinicopathological features and molecular characteristics of sporadic hypertrophic and nodular port-wine stains (PWS).

METHODS

We analysed the clinicopathological and molecular characteristics of 27 sporadic hypertrophic and nodular PWS retrieved from our pathology database from 2013 to 2023 and reviewed the relevant literature.

RESULTS

There were 13 men and 14 women who ranged in age from 10 to 66 years. The main sites were the head and neck (23/27, 85%), which showed irregular thickening and darkening of purplish-red patches on the skin surface and the development of nodularity. Histologically, immature venule-like channels with irregular dilation are arranged in clusters or honeycombs, which are widely distributed primarily in the papillary layer and deep dermis and partly extend into the subcutaneous fat layer and other deep tissues. Dilated vessels with irregular shapes often exhibit fibrous thickening and an increased number of large vessels without vascular endothelial cell proliferation. All vessels showed similar characteristics, with positive staining for CD34, ERG and GNAQ in the endothelial cells, and negative staining for elastic fibres. Nine patients had somatic GNAQ mutations (9/11, 82%), including exon four mutations (6 cases, p.R183Q), exon five mutations (2 cases, p.Q209R) and exon two mutations (one case, p.G48V). Two patients had somatic BCL6 corepressor-like 1 (BCORL1) gene mutations (2/11, 18%), including exon 3 mutations (p.T1111M) and exon 7 mutations (p.G1391R).

CONCLUSIONS

Sporadic hypertrophic and nodular PWS are mostly related to somatic GNAQ mutations. This is the first study to identify the Rare GNAQ G48V and somatic BCORL1 mutations.

Capillary malformations

Capillary malformation (CM), or port wine birthmark, is a cutaneous congenital vascular anomaly that occurs in 0.1%-2% of newborns. Patients with a CM localized on the forehead have an increased risk of developing a neurocutaneous disorder called encephalotrigeminal angiomatosis or Sturge-Weber syndrome (SWS), with complications including seizure, developmental delay, glaucoma, and vision loss. In 2013, a groundbreaking study revealed causative activating somatic mutations in the gene (GNAQ) encoding guanine nucleotide-binding protein Q subunit α (Gαq) in CM and SWS patient tissues. In this Review, we discuss the disease phenotype, the causative GNAQ mutations, and their cellular origin. We also present the endothelial Gαq-related signaling pathways, the current animal models to study CM and its complications, and future options for therapeutic treatment. Further work remains to fully elucidate the cellular and molecular mechanisms underlying the formation and maintenance of the abnormal vessels.

Hematoporphyrin Monomethyl Ether Photodynamic Therapy of Port Wine Stain: Narrative Review

Port wine stain (PWS) is a congenital and progressive capillary malformation characterized by structural abnormalities of intradermal capillaries and postcapillary venules. The visible manifestation is often considered a disfigurement and the accompanying social stigma often causes serious emotional and physical impact. Hematoporphyrin monomethyl ether (HMME) is a newly authorized photosensitizer for treating PWS in China. Hematoporphyrin monomethyl ether photodynamic therapy (HMME-PDT) has successfully treated thousands of Chinese patients with PWS since 2017, and HMME-PDT may be one of the most promising strategies for the treatment of PWS. However, there are few reviews published about the clinical use of HMME-PDT. So in this article, we want to briefly review the mechanism, efficacy evaluation, effectiveness and influencing factors, and the common postoperative reactions and treatment suggestions of HMME-PDT in the treatment of PWS.

GNAQ mutations drive port wine birthmark-associated Sturge-Weber syndrome: A review of pathobiology, therapies, and current models

Port-wine birthmarks (PWBs) are caused by somatic, mosaic mutations in the G protein guanine nucleotide binding protein alpha subunit q (GNAQ) and are characterized by the formation of dilated, dysfunctional blood vessels in the dermis, eyes, and/or brain. Cutaneous PWBs can be treated by current dermatologic therapy, like laser intervention, to lighten the lesions and diminish nodules that occur in the lesion. Involvement of the eyes and/or brain can result in serious complications and this variation is termed Sturge-Weber syndrome (SWS). Some of the biggest hurdles preventing development of new therapeutics are unanswered questions regarding disease biology and lack of models for drug screening. In this review, we discuss the current understanding of GNAQ signaling, the standard of care for patients, overlap with other GNAQ-associated or phenotypically similar diseases, as well as deficiencies in current in vivo and in vitro vascular malformation models.

Pathogenesis of Port-Wine Stains: Directions for Future Therapies

Port-wine stains (PWSs) are congenital vascular malformations that involve the skin and mucosa. To date, the mechanisms underlying the pathogenesis and progression of PWSs are yet to be clearly elucidated. The potential reasons for dilated vessels are as follows: (1) somatic GNAQ (R183Q) mutations that form enlarged capillary malformation-like vessels through angiopoietin-2, (2) decreased perivascular nerve elements, (3) the coexistence of Eph receptor B1 and ephrin B2, and (4) the deficiency of αSMA expression in pericytes. In addition, ERK, c-JNK, P70S6K, AKT, PI3K, and PKC are assumed to be involved in PWS development. Although pulsed-dye laser (PDL) remains the gold standard for treating PWSs, the recurrence rate is high. Topical drugs, including imiquimod, axitinib, and rapamycin, combined with PDL treatments, are expected to alter the recurrence rate and reduce the number of PDL sessions for PWSs. For the deep vascular plexus, photosensitizers or photothermal transduction agents encapsulated by nanocarriers conjugated to surface markers (CD133/CD166/VEGFR-2) possess a promising therapeutic potential in photodynamic therapy or photothermal therapy for PWSs. The pathogenesis, progression, and treatment of PWSs should be extensively investigated.

Multimodality Treatment of Vascular Anomalies of The Head And Neck

Vascular anomalies affect up to 5% of children with the majority affecting the head and neck. They present at different ages as a wide variety of lesions. Careful evaluation with history, physcial examination and imaging assist in the proper diagnosis. Depending on the condition, treatment options for vascular anomalies include topical therapy, selective photothermolysis, sclerotherapy, embolization, surgical excision and targeted systemic therapy. Staged multimodal therapeutic regimens have proven to best control disease and allow for preservation of function and aesthetics. The timing, sequence and combination of therapies is best determined by a multidisciplinary vascular anomalies team. Patients and families need to be counseled on anticipated positive outcomes following a protracted course of treatment for the majority of vascular anomalies.

Enhanced Activation of mTOR Signaling Pathway Was Found in the Hypertrophic and Nodular Lesions of Port Wine Stains

Background

Port wine stain (PWS) is a congenital skin lesion involving capillary malformations. Most PWS lesions will gradually become hypertrophic and appear nodular in contour. Current research shows that rapamycin, an mTOR inhibitor, is probably a promising adjunctive therapy for PWS, which suggests that the mTOR signaling pathway may play an important role in its pathological process.

Methods

From January 2013 to January 2019, 13 samples were obtained during the surgical excision. Each sample was divided into 3 parts according to the type of lesion, namely, the flat, hypertrophic and nodular lesions. Pathologic structures of each type were observed under the microscope after HE staining. The expression of mTORC1, p70S6, p-p70S6, eIF4EBP1 and p-eIF4EBP1 was examined by immunohistochemical staining and western blotting. The location of the expression of mTORC1, p-p70S6 and p-elF4EBP1 was further detected by immunofluorescence staining.

Results

Large amounts of dilated and malformed vessels were observed in all types of PWS lesions. Abundant hyperplastic hair follicles/glands were shown in the hypertrophic or nodular lesions. Phosphorylation level of p70S6 and elF4EBP1 in PWS was significantly higher than those in normal skin and increased accordingly in the progression of PWS. Activated molecules in mTOR signaling pathway were mostly located in the endothelium of malformed vessels. They were also located in the hyperplastic hair follicles/glands of hypertrophic and nodular lesions.

Conclusion

The mTOR signaling pathway was increasingly activated during the progression of PWS. Enhanced activation of mTOR signaling pathway may contribute to the hypertrophy and nodularity of PWS. The results provide preliminary evidence for treating PWS and related syndromes by inhibiting mTOR signaling pathway.