Immunohistochemical Expression of Lymphatic Endothelial Markers in Blue Rubber Bleb Nevus Syndrome.

INTRODUCTION: Blue rubber bleb nevus syndrome (BRBNS) is an uncommon vascular anomaly characterized by multifocal cutaneous, visceral, and other soft tissue or solid organ venous malformations. We observed that BRBNS lesions express immunohistochemical markers of lymphatic differentiation. METHODS: BRBNS histopathologic specimens assessed at our institution during the past 27 years were reviewed. Slides from 19 BRBNS lesions were selected from 14 patients (9 cutaneous, 9 gastrointestinal, and 1 hepatic). We recorded the involved anatomical compartments and presence/absence of thrombi or vascular smooth muscle. Immunohistochemical endothelial expression of PROX1 (nuclear) and D2-40 (membranous/cytoplasmic) was evaluated semi-quantitatively. RESULTS: Endothelial PROX1 immunopositivity was noted in all specimens; the majority (89.5%) demonstrated staining in more than 10% of cells. D2-40 immunopositivity was present in one-third (33%) of cutaneous lesions and only 1 gastrointestinal lesion. CONCLUSION: Endothelial cells in BRBNS almost always express 1 or more immunohistochemical markers of lymphatic differentiation.

Invasive cellular blue nevus in the cervical spine: A case report.

INTRODUCTION: Cellular blue nevus is an uncommon neoplasm in the spine. PATIENT CONCERNS: Here, we present a case of a 24 years old male with a 2 months history of numbness in the right upper limb and shoulder. DIAGNOSIS: Cervical spine and subcutaneous tissue invasive cellular blue nevus. INTERVENTIONS: The patient underwent C4 laminectomy and partial C3 and C5 laminectomy for total resection of the lesion. Histopathology revealed a nodular tumor with unclear boundaries, which was composed of heavily pigmented dendritic cells and more pigmented spindle cells. OUTCOMES: There was no recurrence during 3 years follow-up. CONCLUSION: Invasive cellular blue nevus of the spine can be wrongly diagnosed as spinal meningeal melanocytoma and meningeal melanoma due to its special cell behavior and rarity. Therefore, it is important to understand its pathological and clinical characteristics to avoid over-treatment.

The clinico-pathological spectrum of plaque-type blue naevi and their potential for malignant transformation.

AIMS: Plaque-type blue naevi are rare melanocytic tumours presenting as large, pigmented plaques at birth or during childhood. There is a risk for malignant transformation, but no larger comprehensive studies exist and the diagnosis is challenging, especially on limited biopsy material. The aim is to describe the clinicopathological features and behaviour of the disease more comprehensively. METHODS AND RESULTS: We retrieved eight plaque-type blue naevi, presenting as large, pigmented plaques (median = 7 cm; range = 3-26) most frequently affecting the scalp (four) followed by the cheek, arm, abdominal wall and gluteal cleft (one each), with a slight female predilection. Median age at time of biopsy was 39.5 years (range = 15-90), but three tumours had been present at birth and one since childhood. Histopathologically, the tumours were poorly circumscribed and composed of cellular fascicles of uniform spindle cells in a background of variably prominent pigmented dendritic cells affecting dermis and subcutaneous tissues. The majority had mutations in GNAQ. One tumour showed malignant transformation, characterised by an expansile nodule of pleomorphic epithelioid melanocytes with rhabdoid morphology, high mitotic activity and areas of necrosis. This patient developed metastatic melanoma to lymph nodes. All patients are alive with a median follow-up of 60 months. CONCLUSION: Plaque-type blue naevi are diagnostically challenging tumours with risk for malignant transformation. Awareness and familiarity with the salient clinicopathological features are necessary for reliable diagnosis, and long-term clinical follow-up is required to monitor for malignant transformation.

Treatment options for gastrointestinal bleeding blue rubber bleb nevus syndrome: Systematic review.

OBJECTIVES: Blue rubber bleb nevus syndrome (BRBNS) is a rare challenging cause of gastrointestinal bleeding. We performed a systematic review of case reports and case series on BRBNS to gather information on the treatment options currently available. METHODS: All studies reporting a case of BRBNS in humans were evaluated. Papers were ruled out if CARE criteria and explanations on patient's selection, ascertainment, causality, and reporting were not respected or identified. PROSPERO 2021 CRD 42021286982. RESULTS: Blue rubber bleb nevus syndrome was treated in 106 cases from 76 reports. 57.5% of the population was under 18 years old, and up to 50% of the cases reported a previous treatment. Clinical success was achieved in 98 patients (92.4%). Three main types of interventions were identified: systemic drug therapy, endoscopy, and surgery. After BRBNS recurrence or previous therapy failure, systemic drug therapy emerged as a preferred second-line treatment over endoscopy (P = 0.01), but with a higher rate of reported adverse events when compared with surgery and endoscopy (P < 0.001). Endoscopic treatment was associated with a higher number of required sessions to achieve complete eradication when compared with surgery (P < 0.001). No differences between the three main areas were found in the overall follow-up time (P = 0.19) or in the recurrence rate (P = 0.45). CONCLUSION: Endoscopy, surgery, and systemic drug therapy are feasible treatment options for BRBNS. Systemic drug therapy was the favorite second-line treatment after endoscopic failure or recurrence of BRBNS, but adverse events were more frequently reported.

Verification of the efficacy of topical sirolimus gel for systemic rare vascular malformations: a pilot study.

Numerous clinical trials of sirolimus, an inhibitor of mechanistic/mammalian target of rapamycin complex 1, for the treatment of vascular malformations have been conducted. However, aside from lymphatic malformations, the efficacy of sirolimus for venous and capillary malformations has not been established. Moreover, no generalized venous or capillary malformations have been treated with topical sirolimus. To evaluate the safety and efficacy of topical sirolimus for venous and capillary malformations and to compare the efficacy of topical and systemic sirolimus therapy, an open-label single-arm pilot study with 0.2% sirolimus gel was conducted from July 19, 2019, to January 30, 2020, in four patients diagnosed with different vascular malformations (blue rubber bleb nevus syndrome, common venous malformation, phakomatosis pigmentovascularis type IVb, and angiokeratoma in Fabry disease). The primary endpoint was the safety evaluation of sirolimus gel. The main secondary endpoint was the improvement rate evaluated by the Central Judgment Committee at 12 weeks using photographs. No adverse events were observed. Blood sirolimus was not detected in any patient. Two patients (50%) had mild improvement, and the remaining two patients (50%) showed no change after 12 weeks of treatment. Blue rubber bleb nevus syndrome, a generalized venous malformation, showed the greatest response. In conclusion, 0.2% sirolimus gel was found to be as clinically effective as systemic sirolimus treatment in patients with venous and capillary malformations and more effective for early active lesions, even systemic venous malformations.

PRAME and LEF1 in Combined Deep Penetrating Nevus and Combined Blue Nevus: Utility and Pitfalls.

ABSTRACT: Deep penetrating nevi (DPN), particularly those showing combined features, or combined deep penetrating nevi (CDPN), may show histopathological resemblance to blue nevus (BN) and melanoma. Preferentially Expressed Antigen in MElanoma (PRAME) is a marker that helps distinguish melanoma from benign melanocytic lesions. Lymphoid enhancer-binding factor 1 (LEF1) has been proposed to be used in conjunction with ß-catenin for diagnosis of DPN. The immunohistochemical expression of PRAME and LEF1 was evaluated in 10 DPN (including 6 CDPN and 2 DPN-like proliferations with atypical features), 16 BN (including combined and cellular BN), and 2 melanomas with features of DPN or BN. PRAME was negative in most DPN (n = 10/10, n = 9/10, one case with discrepancy between readers) and all BN (n = 16/16), while the 2 melanomas included were positive (n = 2/2). All DPN were positive for LEF1 (n = 9/9) while only a subset of BN were positive (n = 6/16, P = 0.0028; n = 5/16, P = 0.001, per both readers). LEF1 seemed to be easier to interpret than ß-catenin because of its nuclear pattern of expression. The expression of LEF1 in the regular nevus component of combined BN presents a potential pitfall in practice because it may lead to misinterpretation of LEF1 as positive in the BN component of the lesion. However, a subset (approximately one-third) of combined BN seemed to show true LEF1 expression. Taking into account pitfalls in interpretation, the combinatorial panel of PRAME and LEF1, in addition to conventional histopathological features, may be useful to distinguish CDPN from combined BN and other benign and malignant mimics.

Melanoma arising in plaque-type blue nevus and dermal melanocytosis: Diagnostic and prognostic value of BAP1. / Melanoma sobre nevus azul en placa o sobre melanocitosis dérmicas: utilidad diagnóstica y pronóstica del BAP1.

Melanoma arising in blue nevus, also known as melanoma ex blue nevus, is a specific form of melanoma whose genetic profile is different to that of other cutaneous melanomas and surprisingly similar to that of uveal melanoma. Although melanoma ex blue nevus can appear de novo, it usually arises in a preexisting blue nevus or dermal melanocytosis. Not all nodular lesions arising in association with blue nevus or dermal melanocytosis are melanomas, however, and because clinical and histologic findings may be insufficient for a definitive diagnosis, additional studies such as comparative genomic hybridization are important. Detection of chromosomal aberrations supports a diagnosis of malignancy. Studies of the BAP1 gene are particularly useful in this setting because loss of expression is indicative of melanoma. We present 3 cases on the spectrum of blue nevus to melanoma ex blue nevus that were studied using molecular biology techniques.

TERT Promoter Mutational Analysis as an Ancillary Diagnostic Tool for Diagnostically Challenging Melanocytic Neoplasms.

ABSTRACT: Telomerase reverse transcriptase promoter mutations (TPMs) have been shown to be common in melanoma and uncommon in benign nevi. To assess the use of TPMs as an ancillary diagnostic tool, we report the concordance of the TPM status with the final diagnosis in clinical cases with distinct differential diagnostic scenarios: dysplastic nevus versus melanoma, atypical Spitz nevus versus melanoma, atypical deep penetrating nevus (DPN) versus melanoma, and atypical blue nevus versus malignant blue nevus. In a control cohort, we found a positive TPM in 51/70 (73%) of the total melanomas with the highest frequency in vertical growth phase melanoma cases. Conversely, only 2/35 (6%) dysplastic nevi in our control cases were TPM-positive and b were severely atypical dysplastic nevi. Our clinical cohort of 257 cases had a positive TPM in 24% of cases diagnosed as melanoma and in 1% of cases with a benign diagnosis. The overall concordance of the TPM status with the final diagnosis was 86%. The TPM status had the greatest concordance (95%) with the final diagnosis in the atypical DPN versus melanoma group, with the rest of the groups ranging between 50% and 88%. Overall, our results suggest that TPMs are most useful in the differential diagnosis of atypical DPN versus melanoma. It also has some value in the differential diagnosis of atypical Spitz tumor versus melanoma and dysplastic nevus versus melanoma, whereas in our cohort, it did not contribute meaningfully to differentiating malignant blue nevus and atypical blue nevus.

Blue naevi and the blue tumour spectrum.

Blue naevi (BN) form a wide group of benign dermal melanocytic proliferations. They are genetically distinct from common and Spitz naevi with frequent hotspot mutations occurring in Gαq genes. Clinically, BN display a female predominance, elective sites of emergence and a great variety of subtypes related to specific regions of the skin linked to early embryological genetic events. Histologically, most BN are located in the dermis with small, bland, spindled and dendritic pigmented melanocytes within a fibrous background. Variation in tumour volume, fibrosis, and melanin pigment load can be broad. A growth in size and cellularity can occur within a subset of tumours as they acquire the morphological features of cellular blue naevi, with a biphasic architecture associating a dendritic blue naevus morphology near the surface, and deep vertical cellular expansions of medium-sized, bland melanocytes often reaching the subcutis. Sclerosing and myxoid variants can be observed either as individual or combined modifications that can add complexity to an otherwise straightforward diagnosis. Malignant progression of a cellular blue naevus is exceptional with an intermediate stage named atypical cellular blue naevus. Malignant blue melanomas are fast growing, large, pigmented tumours with most often obvious features of malignancy. However, they are difficult to separate from other malignant dermal melanocytic proliferations. Herein, we will extensively detail and illustrate the clinical, histological and genetic features of the vast spectrum of blue naevi and related entities in the skin.

Blue Rubber Bleb Nevus Syndrome: A Rare Case of Gastrointestinal Hemorrhage Necessitating Bowel Resection.

Blue Rubber Bleb Nevus Syndrome is a congenital rarity that manifests as vascular malformations throughout the body, including the gastrointestinal tract. With fewer than 300 cases reported, the etiology and clinical course is poorly understood; however, the literature suggests TEK mutations on chromosome 9 result in unregulated angiogenesis. We present the case of a young female treated for anemia of unknown etiology who presented in hemorrhagic shock due to gastrointestinal hemorrhage necessitating small bowel resection, with cutaneous, intestinal, hepatic, and lingual vascular malformations associated with a single somatic pathologic TEK mutation. Although uncommon, this case suggests that Blue Rubber Bleb Nevus Syndrome should be considered in the differential of a patient with persistent anemia and cutaneous lesions, carrying the potential for multiple gastrointestinal vascular malformations progressing to hemorrhage necessitating operative management. Additionally, a severe phenotype can occur without a double-hit TEK mutation.

Two congenital cases of pigmented epithelioid melanocytoma with unique clinical and genetic features.

Pigmented epithelioid melanocytomas (PEM) are intermediate-grade melanocytic lesions with frequent lymph node involvement and rare metastases that tend to follow an indolent course with a favorable outcome. We report two unique cases of congenital PEM with PRKCA fusion transcripts: a multifocal PEM with an aggressive incompletely resectable scalp tumor and a solitary palmar PEM with newly reported ITGB5-PRKCA fusion. Through these case reports and a summary of previously reported cases, we outline the spectrum of disease of PEM and highlight the key clinical and histopathologic features associated with PEM with PRKCA fusion transcripts. We also discuss the treatment options and suggest that surgical excision without further adjuvant systemic treatment is reasonable first-line therapy given the favorable prognosis.

Treatment of sirolimus in the pathological femoral fracture related to blue rubber bleb nevus syndrome: A case report.

RATIONALE: Blue rubber bleb nevus syndrome (BRBNS) is a rare condition with characteristic vascular malformations of the skin, most frequently lesions of the gastrointestinal tract and central nervous system, and less often, the musculoskeletal system. We report a 5-year case of BRBNS complicated with pathological femoral fracture that was successfully treated with sirolimus. PATIENT CONCERNS: We report the case of a 1-week-old girl with a diagnosis of BRBNS who had multiple venous malformations over her body. She also presented with right lower-limb swelling and complicated with a pathological femoral fracture. DIAGNOSES: BRBNS with the complication of pathological femoral fracture. INTERVENTIONS: Treatment with low-dose sirolimus as an antiangiogenic agent was administered, combined with hip spica protection. OUTCOMES: The vascular lesion was reduced after about 6 months and the fracture site had healed around 2.5 years after initiation of sirolimus therapy. There were no drug adverse effects at the 5-year follow-up point. The patient showed excellent spirit and no obvious sequelae were found. LESSONS: To the best of our knowledge, this is the first report of the successful use of sirolimus in a patient with a pathological femoral fracture related to BRBNS complications.

Clipping with double-balloon endoscopy for small intestinal venous malformations in a patient with blue rubber bleb nevus syndrome.

Blue rubber bleb nevus syndrome (BRBNS) is a rare syndrome characterized by venous malformations in the skin and gastrointestinal tract, especially in the small intestine. Patients with BRBNS have increased risks of gastrointestinal hemorrhage and anemia. This is the first report in the English literature on BRBNS with hemangiomas in the small intestine that were treated successfully by endoscopic clipping using double-balloon endoscopy. A 25-year-old Japanese man presented to a local clinic with dyspnea, fatigue, and a hemoglobin level < 5 g/dL. The diagnosis was iron deficiency anemia. Since childhood, he had had a hemangioma in the shoulder joint and hemangiomas in the skin on the left arm. However, neither upper nor lower gastrointestinal endoscopy showed any lesions and he was referred to us for further evaluation and treatment of the anemia. Small bowel capsule endoscopy (SBCE) revealed hemangiomas in the small intestine, one of which was bleeding. Transanal DBE revealed a 10-mm bluish-purple hemangioma with erosion on the surface, which became smaller after application of five clips. Follow-up SBCE on day 50 showed that the hemangioma had completely disappeared. Clipping may be a safe and effective treatment for small bowel hemangioma in BRBNS.

Blue nevi of the palpebral conjunctiva: report of 2 cases and review of literature.

PURPOSE: To describe two patients with blue nevi of the palpebral conjunctiva and to review the existing literature on common and cellular blue nevi of the conjunctiva. METHODS: Report of two cases and literature review. RESULTS: We present two cases of blue nevi in the palpebral conjunctiva: an atypical cellular blue nevus of the left upper eyelid and a common blue nevus around the lacrimal punctum of the left lower eyelid. Both patients underwent full thickness eyelid excision with wide margins. There was no tumor recurrence at 11 and 4 months postoperatively. CONCLUSIONS: Blue nevi are a group of melanocytic tumors that rarely involve the ocular adnexa. They may arise in the palpebral conjunctiva and should be considered in the differential diagnosis of pigmented lesions in this location as they can mimic melanoma.

Subungual melanoma with blue naevus-like morphological features: a clinicopathological retrospective analysis of nine cases.

Melanocytic lesions in the nail apparatus are often challenging. Both subungual melanomas (SUM) and blue naevus of the nail are very rare. Occasionally, melanomas may mimic blue naevus histologically. Benign and malignant blue melanocytic lesions are commonly associated with G protein mutations, a distinct abnormality not associated with conventional subungual melanomas. We describe the clinical, histological and immunohistochemical features of nine cases of SUM with blue naevus-like morphological features. Mutations in exon 4 and 5 of GNAQ and GNA11 were investigated in two cases, which showed no mutations. RNA-seq of one case revealed unknown mutations along with mutations in ATM, METK and ARID1A. Our study delineates a variant of SUM that mimics blue naevus. Awareness of this pitfall is important when evaluating heavily pigmented lesions around the nail in order to avoid misdiagnosis. Appropriate sampling of subungual lesions and clinicopathological correlation are paramount to reach the correct diagnosis.

Blue rubber bleb nevus syndrome in a Pakistani child: A case report and regional literature review.

Blue rubber bleb nevus syndrome (BRBNS) is a rare disorder in which there is development of multiple venous malformations and haemangiomas in the skin and visceral organs. The lesions mostly involve the skin and gastrointestinal systems but other organs, including the liver, muscles, and the central nervous system, can also be involved. If untreated, affected individuals develop severe anaemia. Most cases are managed with iron supplementation and blood transfusions but some may require surgical resection, endoscopic sclerosis and laser photocoagulation. Here, we present a case of BRBNS in a four-year-old girl with multiple cutaneous lesions, melena and severe anaemia. Review of South Asian literature showed that only two cases (besides ours) have been reported from Pakistan and the rest were from India. This highlights the lack of awareness of BRBNS among physicians in Pakistan and the rest of South Asian countries.