Blue Nevi of the Müllerian Tract: Case Series and Review of the Literature

Large Plaque-type Blue Nevus with GNAQ Q209P Mutation, Involving Mammary Gland Tissue: Under-Recognized Mammary Condition as an Origin of Primary Mammary Melanocytic Tumors

ABSTRACT

Plaque-type blue nevus is a rare variant of blue nevi that was first described in 1954. This article presents clinical, macroscopic, histopathological, and genetic findings for a case of large plaque-type blue nevus expanding into the mammary gland tissue as well as the skin of the right breast. A 63-year-old woman presented with a congenital, large, blue-colored macule limited to the hypochondriac area of the right breast. A nodule 8 mm in diameter was also present in the mammary gland tissue. Magnetic resonance imaging was unable to detect diffuse melanin deposition in the mammary gland tissue, but pigmentation in the whole mammary parenchyma was observed in the cut surfaces of the mastectomy specimen. Histopathology revealed a sparse distribution of dendritic melanocytes in whole sections of the mammary fibrous tissue and partial sections of the dermis. The histopathological criteria for atypical cellular blue nevus were fulfilled for the mammary tumor. Nodal blue nevus was diagnosed in the sentinel lymph node. Sanger sequencing confirmed the GNAQ Q209P mutation, which was also identified in all 4 literature cases of plaque-type blue nevus, but rarely in conventional blue nevi and uveal melanoma. It should be noted that plaque-type blue nevus can expand into the mammary gland tissue, even if the pigmented lesion does not exist on the overlying breast skin. The mammary condition can be the origin of primary mammary melanocytic tumors. Mosaicism of the GNAQ Q209P mutation can be a characteristic genetic alteration to extensive blue nevi, including plaque-type blue nevus.

Uterine Cellular Blue Nevus Arising in Mullerian and Pelvic Dendritic Melanocytosis: Case Report of a Rare Phenomenon to Be Distinguished From Uterine Melanoma

A 37-yr-old woman presented to the gynecology clinic with abnormal uterine bleeding in the setting of known, large uterine fibroids. Preoperative endometrial biopsy identified atypical melanocytic cells concerning for uterine melanoma. Care was transferred to the gynecologic oncology service for hysterectomy. Intraoperative findings included macular, blue-black pigmentation of the peritoneum of the bladder and cervix, which was resected and sent for frozen section, confirming melanocytic neoplasia. The hysterectomy revealed multiple tan leiomyomas up to 12 cm, and a distinct 3 cm black, incompletely circumscribed mass in the endomyometrium composed of bland spindled cells with delicate melanin granules. The tumor cells were positive for Sox-10, BAP1, and Mart-1 (Melan-A) and negative for PRAME, PD-L1, and BRAFV600E by immunostains. Microscopic elements of similar melanocytes and melanophages were found in the cervix and bladder peritoneum. Molecular analysis of the uterine tumor identified a GNA11 mutation but no TERT or BAP1 mutation. The uterine melanocytic tumor has characteristic findings of a cellular blue nevus arising in association with dendritic melanocytosis of Mullerian and pelvic tissues, a rarely seen benign phenomenon that should be distinguished from malignant melanoma of the upper genital tract.

Primary intra-abdominal melanoma arising in association with extracutaneous blue naevus: a report of two cases

AIMS

Blue naevi are uncommon dermal melanocytic neoplasms characterised by GNAQ/GNA11 mutations, which very rarely progress to melanoma. Such melanomas also often have BAP1 mutations, and lack genetic events associated with conventional melanoma. Exceptionally, blue naevi arise in extracutaneous locations; one melanoma arising in this setting has been reported. We report the clinicopathological, immunohistochemical and molecular genetic features of two cases of melanoma arising in extracutaneous blue naevus.

METHODS AND RESULTS

Both arose in males, aged 25 and 63 years, with no history of other melanocytic lesions, and presented as large, painful intra-abdominal masses. The tumours were dark-brown/black, multilobulated, involved small intestinal mesentery and consisted of a predominantly fascicular and spindled, but occasionally nested and epithelioid, proliferation of variably pigmented, relatively monotonous cells with pale cytoplasm and ovoid nuclei with mild to moderate atypia. Mitotic activity was variable but generally low. Both cases showed areas of conventional and cellular blue naevus. Recurrent tumour in one case showed predominantly epithelioid morphology and greater cytological atypia and mitotic activity. One case expressed Melan-A, SOX10 and CD117, with absent expression of S100 protein and DOG1; the other expressed Melan-A, HMB45 and S100 protein. Next-generation sequencing identified GNAQ and BAP1 mutations in one case and GNA11 mutation in the other. Both patients developed widespread metastatic disease.

CONCLUSION

Exceptionally rare, aggressive melanomas arising in extracutaneous blue naevi should be distinguished from metastatic melanoma, gastrointestinal stromal tumour and malignant melanotic nerve sheath tumour, especially given the significant therapeutic and prognostic differences between these different entities.

A Rare Case of Multifocal Prostatic Blue Nevus

Prostatic blue nevus is a rare benign pathologic diagnosis most commonly diagnosed incidentally on many different types of prostate specimens. Blue nevus is the deposition of stromal melanin characterized by spindle cells within the fibromuscular stroma which stains positive for melanin-specific stains Fontana-Masson and S100 and stains negative for CD68, HMB45, and iron stains. We report the case of a multifocal and bilateral blue nevus in a 52-year-old Hispanic male who presented with an elevated prostate-specific antigen of 4.3 and mild obstructive lower urinary tract symptoms, found by transrectal ultrasound-guided prostate needle biopsy. The biopsy also revealed benign prostatic tissue with postatrophic hyperplasia and chronic inflammation. This is the 35th reported case of prostatic blue nevus and the third to show multifocal blue nevus.

The spectrum of grossly visible pigmented lesions in the uterine cervix: a prospective study

Pigmented lesions of the uterine cervix (UC) have not been systematically studied in the literature. Over an 18-mo period, we prospectively investigated the histologic spectrum of all macroscopically visible pigmented lesions of the UC. The incidence of pigmented UC was 1.6% (33/2118). Histologic examination revealed 32 cases (97%) with a histologic correlate, of which 26 lesions were of melanocytic nature including 25 blue nevi (BNs) (81%) and 1 melanotic macule (3%). The nonmelanocytic lesions included 1 case of focal granulomatous vasculitis (3%), 2 biopsy site-associated reactive changes with hemosiderin-laden macrophages (6.4%), 1 case of hemorrhagic Nabothian cyst (3%), 1 hemangioma (3%), and 1 case of multinucleated giant cell reaction to dark black carbon-like material (3%). Women with UC BN (1.2% incidence) were mostly whites (13/25, 52%) with a mean age of 47.4 yr (range, 31-64 yr). The number and size of BN per UC, all located in the endocervix, varied between 1 to 3 and 0.1 to 2 cm (mean, 0.68 cm). UC BN exhibited 3 distinct morphologic patterns: (1) stromal melanocytic focus composed of fine spindle cells (9/25, 36%); (2) mixed pattern with fine spindle, plump spindle, and epithelioid cells (15/25, 60%); and (3) nevoid stage with epithelioid cells (1/25, 4%). In contrast, cervical melanotic macule was located in the squamous epithelium of the ectocervix and characterized by hyperpigmentation of the basal keratinocytes admixed with scattered slightly enlarged melanocytes. In conclusion, pigmented lesions of the UC are not as uncommon as reported and mostly benign in nature. Several cases may require deeper levels for their detection and to exclude the rare phenomenon of UC melanoma.

Endometrioid adenocarcinoma concurrent with a blue nevus of the endometrium and uterine cervix: A case report

A blue nevus is a benign melanocytic lesion that is composed of spindle-shaped pigmented melanocytes. Although the uterine cervix is believed to be the most common extracutaneous location of blue nevi, the occurrence of these lesions in the endometrial stroma has been reported, albeit rarely. The present study describes a case of endometrioid adenocarcinoma concurrent with a blue nevus of the endometrium and uterine cervix. A 58-year-old female presented with abnormal vaginal bleeding. A biopsy from the endometrium revealed an endometrioid adenocarcinoma and subsequently, a total hysterectomy was performed. Histopathological study revealed the proliferation of columnar cells that formed irregularly-shaped tubular and cribriform glands. The neoplastic columnar cells had large, round to oval nuclei containing a single small nucleolus. Focal squamous differentiation was noted. In the stroma of the non-neoplastic endometrium, single or small aggregates of short spindle-shaped cells containing melanin without atypia were observed. These melanocytes were also present in the endocervix. Therefore, the final diagnosis was of endometrioid adenocarcinoma concurrent with a blue nevus of the endometrium and cervix. This is the first documented case of a blue nevus of the endometrium and endocervix. The pathogenesis of blue nevi of the genital tract is not yet completely understood. Possible origins of these cells include Schwann cells or perineural cells of the peripheral nerve fiber or the abnormal migration of neural crest-derived cells.

Sinonasal blue naevus: case report and clinicopathological review

OBJECTIVE

To highlight the important clinical and histological features of sinonasal blue naevi.

METHODS

A case of blue naevus of the nasal cavity is described (including endoscopic and histological pictures) and the existing literature is reviewed.

RESULTS

There have been five reported cases (including the presented case). Clinically, sinonasal blue naevi are heavily pigmented lesions that are small and asymptomatic. Histopathologically, blue naevi exhibit heavily pigmented dendritic melanocytes that are never abnormal in form.

CONCLUSION

Blue naevus should be a differential diagnosis for pigmented lesions within the sinonasal cavity, despite its rarity. It may be initially suspected by its small size and asymptomatic nature. However, histological examination is required for definitive diagnosis, looking for the key microscopic features described above.

Combined nevus of the tarsal conjunctival

We present an unusual case of combined nevus of the tarsal conjunctiva and eyelid margin in a pregnant woman who noticed morphological changes of the lesion during pregnancy. The patient underwent a wide full-thickness eyelid excisional biopsy including tarsal conjunctiva. Histopathologically, a subepithelial combined nevus (nevocellular and blue nevus) was observed. Conjunctival nevi are benign lesions with wide variation in clinical and histopathological features. Tarsal conjunctival involvement, as in the present case, is extremely rare (less than 1% of conjunctival nevi), especially the blue type nevus. Definitive diagnosis is possible only with excisional biopsy.

Amelanotic cellular blue nevus: an unusual iris localization

The authors describe the first case of eye amelanotic cellular blue nevus reported in literature and discuss the main differential diagnosis.

Vaginal blue nevus: report of a case and review of the literature

OBJECTIVE

: Blue nevi are extremely rare in the vaginal canal and are suspicious for melanoma, especially when multiple lesions are present. We describe a woman with multiple blue nevi of the vagina.

DESIGN

: We describe 1 case of multiple blue nevi of the vagina.

RESULTS

: A 37-year-old woman, status after therapy for serous carcinoma of the ovary, presented with multiple blue to black macular lesions present throughout the vagina. Two of the lesions were examined by biopsy and demonstrated dendritic melanocytes. The patient has been closely followed, and the lesions remain unchanged.

CONCLUSIONS

: Multiple vaginal blue nevi are an important differential diagnostic consideration for melanoma of the vagina. These lesions, however, are benign and require only clinical follow-up. Excision is unnecessary.

Angiomatoid giant cellular blue nevus of vaginal wall associated with pregnancy

Background

Blue nevi that arise from the Müllerian tract are rare melanocytic lesions. Several histopathologic variants of cellular blue nevi have been described. The angiomatoid variant is characterized by a vascular component, and is considered to be a rare variant. Few studies have explored the influence of pregnancy on melanocytic lesions.

Case

A 29-year-old woman was presented with a pigmented vaginal lesion that increased gradually during pregnancy. A full term gynecologic examination showed a tumor mass protruding into the vaginal canal. The mass was resected during cesarean-section under the clinical impression of vaginal hemangioma.

Result

Gross examination revealed a cystic mass measuring 6.0 × 4.3 × 3.5 cm, which was filled with dark friable material. Histologically, the mass showed a subepithelial cellular proliferation of heavily pigmented dendritic melanocytes with prominent vascular stroma. Cytologic pleomorphism, junctional activity, atypical mitosis, and necrosis were not found. The proliferation was immunoreactive for HMB-45, S-100 and melan-A, and non-immunoreactive for CD34, smooth muscle actin, and AE1/AE3. The MIB-1 proliferative index was less than 1%. The patient had a postoperative course without complication.

Conclusions

Angiomatoid giant cellular blue nevus arising from the vagina during pregnancy is extremely rare. The low proliferative index and absence of cytologic pleomorphism, or necrosis, supports a benign biological behavior. Clinical follow-up showed no evidence of recurrence at one year after the resection of the mass.

Cellular blue nevus of the uterus: a case report and review of the literature

Cellular blue nevus is extremely rare in the gynecologic tract with only 2 cases reported thus far, one in the myometrium and the other in the cervix/vagina/hymenal ring. In this report, we present the clinicopathologic features of the second case of cellular blue nevus arising in the myometrium. The patient was a 48-year-old woman who underwent a hysterectomy with bilateral salpingo-oophorectomy for uterine leiomyomas. On gross examination, the uterus showed a subserosal, 1.0×0.5×0.3 cm, dark red nodule in the anterior uterine wall in addition to multiple leiomyomas. Microscopically, the subserosal dark nodule had an irregular contour with only focal areas of pushing circumscribed border. The tumor cells were arranged either in sheets or confluent nests. The tumor cells were mostly epithelioid with clear cytoplasm, but in some areas the tumor cells were spindle-shaped with eosinophilic cytoplasm. Both types of cells contained intracytoplasmic melanin. The nuclei of the tumor cells were either oval, round, or elongated with no or minimal irregularities of the nuclear membrane, evenly distributed chromatin, inconspicuous nucleoli, and no obvious mitotic figures. Focally some of the epithelioid cells showed enlargement of the nucleus, irregularities in the nuclear contour, and rare nuclear pseudoinclusions. The tumor cells were positive for S-100, HMB-45 antigen (strong and diffuse pattern), and MART-1. Anti-Ki-67 showed a low proliferative activity (only a rare cell marked for this immunomarker). Thus, a diagnosis of cellular blue nevus was established. After a follow-up of 2 months, the patient had no evidence of the disease.

Benign masses of the female periurethral tissues and anterior vaginal wall

Due to their rarity, benign masses of the periurethral tissues and anterior vaginal wall are poorly understood. Arriving at the proper evaluation and treatment is challenging because many of these masses have similar presenting signs and symptoms, as well as overlapping differential diagnoses. The literature regarding these lesions mainly consists of level III evidence, mostly involving case reports and series. Clinical management has traditionally been based on established surgical principles and expert opinion. This review presents the pertinent embryologic and anatomic background for these benign masses, as well as other pertinent etiological processes. Furthermore, the most current evidence is reviewed regarding the differential diagnosis, evaluation, and treatment for each mass.