Blue nevi are benign proliferations of melaninproducingdendritic melanocytes located in thedermis. These nevi tend to occur mostly on the skin,predominantly on the head and neck, dorsal aspectsof the distal extremities, and the sacral area, butcan also occasionally appear on mucosal surfaces.Blue nevi of the nail apparatus are uncommon. Themajority originate in the nail matrix where there is ahigher density of melanocytes. Herein we report ona 47-year-old man with a rare common blue nevus ofthe nail bed, an area with low melanocyte density. Athorough review of the English language literaturefound no documented cases of acquired blue nevioriginating in the nailbed of the toe

Berke, Adrienne

Klufas, Daniel M

Que, Syril Keena T

Sloan, Brett

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UC DavisDermatology Online JournalTitleAcquired blue nevus of the nail bedPermalinkhttps://escholarship.org/uc/item/66c1m1hmJournalDermatology Online Journal, 23(2)AuthorsKlufas, Daniel MQue, Syril Keena TBerke, Adrienneet al.Publication Date2017DOI10.5070/D3232033963Copyright InformationCopyright 2017 by the author(s).This work is made available under the terms of a Creative Commons Attribution-NonCommercial-NoDerivatives License, available at https://creativecommons.org/licenses/by-nc-nd/4.0/ Peer reviewedeScholarship.org Powered by the California Digital LibraryUniversity of CaliforniaVolume 23 Number 2 | February 2017 DOJ 23 (2): 3- 1 - Dermatology Online Journal  ||  Case ReportDaniel M. Klufas BS, Syril Keena T. Que MD, Adrienne Berke MD, Brett Sloan MDAffiliations: Department of Dermatology, University of Connecticut Health Center, Farmington, Connecticut, USACorresponding Author: Steven Brett Sloan, MD, Associate Professor of Dermatology, VA Site Director, University of Connecticut Health Center, Department of Dermatology, 21 South Road, Suite 200, Farmington, CT 06030-6231, Tel: 860-679-4600, Email: Steven.Sloan@va.govAcquired blue nevus of the nail bedKeywords: blue nevus, nail apparatus, benign melanocytic lesions, subungual melanomaIntroductionBlue nevi are dermal melanocytic proliferations that are histologically characterized by dermal spindle-shaped and pigmented bipolar dendritic cells [1,2]. This generally benign skin tumor can be congenital or acquired. The nevi usually present as gray-blue or brown-blue solitary nodules or plaques, often found on the skin of the head and neck, dorsum of distal extremities, and pre-sacral regions and occasionally in the oral cavity [3] and mucosal surfaces. Nevi on the nail apparatus, however, are quite rare with only eleven cases currently documented in the literature, only two of which document cases in the nail bed [4,5]. Although blue nevi are typically benign, there have been reports of malignant degeneration particularly of the cellular variant [1,2,6]. Nonetheless, careful examination and evaluation should be performed in order to differentiate between a blue nevus and a subungual malignant melanoma, which carries a poor prognosis. We report here on a 47-year-old Japanese man with an acquired blue nevus in the nail bed of his right first toe and discuss clinical and pathologic characteristics of this rare finding.Case SynopsisA 47-year-old Japanese man with a family history of acral lentiginous melanoma presented to clinic with a blue macule under the right first toenail, which had been present for one year. He denied any pain or tenderness and reported that the lesion had been stable in size. Physical examination showed a 2 mm blue circular macule on the nail bed immediately distal to the lunula of the right first toe (Figure 1). AbstractBlue nevi are benign proliferations of melanin-producing dendritic melanocytes located in the dermis. These nevi tend to occur mostly on the skin, predominantly on the head and neck, dorsal aspects of the distal extremities, and the sacral area, but can also occasionally appear on mucosal surfaces. Blue nevi of the nail apparatus are uncommon. The majority originate in the nail matrix where there is a higher density of melanocytes. Herein we report on a 47-year-old man with a rare common blue nevus of the nail bed, an area with low melanocyte density. A thorough review of the English language literature found no documented cases of acquired blue nevi originating in the nailbed of the toe.Figure 1. Well-demarcated blue spot on right first toenail.Volume 23 Number 2 | February 2017 DOJ 23 (2): 3- 2 - Dermatology Online Journal  ||  Case ReportDermoscopy showed a homogenous blue blotch. A punch biopsy of the nail bed revealed dendritic melanocytes containing fine melanin and numerous polygonal macrophages containing abundant coarse melanin throughout a fibrotic reticular dermis (Figure 2). A MART-1 immunohistochemical stain was positive for dermal melanocytes and a Fontana-Masson stain was positive for dermal pigment (Figure 3). The patient was diagnosed with an acquired common blue nevus on the nail bed, which was completely removed by punch biopsy. No recurrence of the blue nevus was noted on follow-up.Case DiscussionA blue nevus is a pigmented lesion caused by proliferating melanocytes in the dermis, usually presenting as a single, small dark blue or blue-black macule or dome-shaped papule. The unique blue color of these nevi is attributed to the Tyndall effect, which causes the skin to reflect shorter wavelengths of the blue spectrum [2].The predominant theory regarding the pathogenesis of blue nevi is that they arise from aberrant dendritic melanocytes that fail to completely travel from the dermis to epidermis during embryologic migration of melanocytes [7]. Additionally, inflammation or other insults may play a role in inducing proliferation of the aforementioned aberrant melanocytes, resulting in acquired blue nevi [8].Melanocytic nevi of the nail apparatus are extremely rare simply because the number of melanocytes in the nail are much lower than the number in the skin. For comparison, the epidermis has a melanocyte density of about 1150/mm2 whereas the nail matrix has about 200/mm2. What makes our case truly unique is that our patient’s nevus involved the nail bed, where melanocytes are even rarer, often completely absent or having a density of only 50/mm2. Furthermore, nail bed melanocytes are, by nature, entirely dormant, meaning they produce no pigment [9]. !Figure 2. Histopathology of biopsy of blue nevus. (A) Hematoxylin-eosin stain; original magnification x10 (B) Hematoxylin-eosin stain; original magnification x20 (C) Hematoxylin-eosin stain; original magnification x40 (D) Hematoxylin-eosin stain; original magnification x100!Figure 3. Histopathology of biopsy of blue nevus. (A) Fontana-Masson silver stain showing that the lesion is staining positively for dermal melanin pigment; original magnification x10 (B) MART1 (Melan-A) stain to highlight dermal melanocytes of the lesion; original magnification x10Volume 23 Number 2 | February 2017 DOJ 23 (2): 3- 3 - Dermatology Online Journal  ||  Case ReportGiven the quiescent nature of nail bed melanocytes and their sheer low number, it should come as no surprise that melanocytic nevi are rarely observed in clinical practice. Our report of a nail bed nevus is only the third such report in the literature, and the sole case of an acquired blue nevus of the toenail bed (Table 1). Table 1 illustrates that common blue nevi are the most common type found on the nail apparatus with five such documented cases. Blue nevus is often found as a single nevus; multiple nevi should raise concerns for Carney complex, or NAME/LAMB syndromes [10]. Only one case of subungual blue nevus has been associated with a syndrome [11].Despite the generally benign nature of blue nevi, malignant transformation has been reported, particularly in the compound variant with dermal-epidermal junction involvement [6,12]. Malignant blue melanoma is a rare form of aggressive melanoma that can arise in a common/cellular blue nevus or at sites of previous excision. A malignant blue nevus is characterized by tumor necrosis, high grade epithelioid cell atypia, pleomorphic nuclei, and high mitotic activity [13]. As such, subungual blue nevi require a detailed work-up and thorough consideration of the differential diagnosis, including subungual malignant melanoma, which represents between 0.7 and 3.5% of all cutaneous melanoma Table 1. Reported cases of blue nevi of nail apparatusSource Age Gender Location Clinical findings Histology Onset Syndrome? RecurrenceVidal et al. [20] 20 M Right foot, first toeBlue-black nodule at distal edge of nail plate with hypony-chium involvementCommon blue nevus (no junction-al compo-nent)Congenital No NRSoyer and Kerl [11] 4 FLeft foot, first toe N/ACombined blue nevus CongenitalYes - Klip-N/ASalasche and Garland [21] NR NR ThumbLongitudinal mela-nonychia NR NR NR NRKim et al. [4] 44 FRight hand, thumbLongitudinal mela-nonychia and blue discoloration in lunar area; involved prox-imal nail bed and distal nail matrixCommon blue nevus Acquired No NRS m i t h , Morgan, and B e t t e n c o u r t [22]61 MRight hand, third fingerCommon blue nevus Acquired No – 2 yearsDalle et al. [23] 34 FRight hand, second fingerBlue gray macule in middle of lunula; superficial linear erosion of nail plate extended from distal part of tumor process to the distal nail plateCommon blue nevus Acquired No No – 2 yearsCauseret et al. [24] 42 FLeft foot, first toeOvoid-shaped blue pigmentation of dis-tal nail matrix areaCellular blue nevus Acquired No No – 1 year Volume 23 Number 2 | February 2017 DOJ 23 (2): 3- 4 - Dermatology Online Journal  ||  Case ReportSource Age Gender Location Clinical findings Histology Onset Syndrome? RecurrenceMoulonguet-Michau and Abimelec [25]5242FM1) Left first toe2) Right hand, thumbBlue-black maculeBlue-black maculeCellular blue nevus (?)Cellular blue nevus (?)AcquiredAcquired NoNoNo – 3 yearsNo – 2 yearsNaylor et al. [26] 40 FLeft hand, fourth fingerDark blue dyschro-mia under proximal nail plate, overlying proximal nail bed and extending under proximal nail foldCombined blue nevus – arising from directly beneath the nail bed and matrix epithelium, forming nodule in the dermisAcquired No No – 12 monthsGershtenson et al. [5] 21 FRight foot, second toeIrregularly shaped, sharply delineated blue-black plaque extending to the cuticle, proximal and lateral nail fold, and adjacent nail bed and hyponychium Cellular blue nevus Congenital No No – 1 yearOur case 47 M Right foot, first toeBlue circular macule on nail bedCommon blue nevus Acquired No No [14]. However, the incidence is significantly higher in the Japanese population, estimated to be as high as 23% [15]. This was of particular concern in our patient given his Japanese ethnicity and family history of acral lentiginous melanoma. Clinical signs such as enlargement of the nevus, nail dystrophy, or periungual extension should raise concern for possible subungual melanoma [5]. Other potential causes for similar appearing lesions include argyria [16-18], glomus tumor, Wilson disease, iatrogenic pigmentation by drugs such as minocycline or zidovudine, and occupational exposures [19]. Once the diagnosis of subungual blue nevus is confirmed, treatment options may include complete excision, as performed in our patient. However, excision of larger nevi does increase the risk of nail dystrophy or even functional impairment of the affected digit [5].ConclusionA blue nevus is a unique neoplasm caused by the dermal proliferation of melanocytes. Although they can be located anywhere on the body, blue nevi of the nail bed are extremely rare and can be mistaken for glomus tumors or drug-induced pigmentation. Blue nevi have an excellent prognosis, but providers must biopsy to rule out the possibility of a subungual melanoma.References1. Ferrara G, Soyer HP, Malvehy J et al. The many faces of blue nevus: a clinicopathologic study. J Cutan Pathol 2007;34:543-51. [PMID:17576333]2. Zembowicz A, Mihm MC. Dermal dendritic melanocytic proliferations: an update. Histopathology 2004;45:433-51. [PMID:15500647]3. Rask KR, Topp CW, Tilson HB. Intraoral blue nevus: review of the literature and report of case. J Oral Surg 1972;30:212-4. [PMID:4551116]4. Kim HS, Kim YJ, Kim JW, Yu DS. Subungal blue nevus. J Eur Acad Dermatol Venereol 2007;21:271-2. [PMID:17243978]5. Gershtenson PC, Krunic A, Chen H et al. Subungual and periungual congenital blue naevus. Australas J Dermatol 2009;50:144-7. [PMID:19397572]6. Elder DE, Elenitsas R, Murphy GF, Xu X. Benign pigmented lesions and malignant melanoma. In: Elder DE, Elenitsas R, Johnson BL Jr, Murphy GF, editor. Lever’s Histopathology of the Skin, Philadelphia: Lippincott-Raven; 1997, p. 717-718-721.7. Leopold JG, Richards DB. The interrelationship of blue and common naevi. J Pathol Bacteriol 1968;95:37-46. [PMID:5643464]8. Hori Y, Kawashima M, Oohara K, Kukita A. Acquired, bilateral nevus of Ota-like macules. J Am Acad Dermatol 1984;10:961-4. [PMID:6736340]9. Perrin C, Michiels JF, Pisani A, Ortonne JP. Anatomic distribution of melanocytes in normal nail unit: an immunohistochemical investigation. Am J Dermatopathol 1997;19:462-7. [PMID:9335239] 10. Rhodes AR, Silverman RA, Harrist TJ, Perez-Atayde AR. Mucocutaneous lentigines, cardiomucocutaneous myxomas, and Volume 23 Number 2 | February 2017 DOJ 23 (2): 3- 5 - Dermatology Online Journal  ||  Case Reportmultiple blue nevi: the “LAMB” syndrome. J Am Acad Dermatol 1984;10:72-82. [PMID:6693605]11. Soyer HP KH. European society of pediatric dermatology clinical case reports 1984. In: Baran R, Dawber RPR, Berker DAR, Haneke E, Tosti A, editor. Diseases of the Nails and Their Management, Oxford: Blackwell Science Ltd; 2001, p. 616-617-618.12. Gonzalez-Campora R, Galera-Davidson H, Vazquez-Ramirez FJ, Diaz-Cano S. Blue nevus: classical types and new related entities. A differential diagnostic review. Pathol Res Pract 1994;190:627-35. [PMID:7984522]13. Zembowicz A, Phadke PA. Blue nevi and variants: an update. Arch Pathol Lab Med 2011;135:327-36. [PMID:21366456]14. Levit EK, Kagen MH, Scher RK et al. The ABC rule for clinical detection of subungual melanoma. J Am Acad Dermatol 2000;42:269-74. [PMID:10642684]15. Kato T, Suetake T, Sugiyama Y et al. Epidemiology and prognosis of subungual melanoma in 34 Japanese patients. Br J Dermatol 1996;134:383-7. [PMID:8731657]16. Bergfeld WF, McMahon JT. Identification of foreign metallic substances inducing hyperpigmentation of skin: light microscopy, electron microscopy and x-ray energy spectroscopic examination. Adv Dermatol 1987;2:171-83. [PMID:3274957]17. Sarsfield P, White JE, Theaker JM. Silverworker’s finger: an unusual occupational hazard mimicking a melanocytic lesion. Histopathology 1992;20:73-5. [PMID:1737629]18. Bleehen SS, Gould DJ, Harrington CI et al. Occupational argyria; light and electron microscopic studies and X-ray microanalysis. Br J Dermatol 1981;104:19-26. [PMID:7459266]19. Baran R, Dawber R, de Berker DAR, Haneke E, Tosti A. Baran and Dawber’s Diseases of the nail and their management. London (UK): Blackwell Science, 2001.20. Vidal S, Sanz A, Hernandez B et al. Subungual blue naevus. Br J Dermatol 1997;137:1023-5. [PMID:9470936]21. Salasche SJ, Garland LD. Tumors of the nail. Dermatol Clin 1985;3:501-19. [PMID:3006954]22. Smith DF, Morgan MB, Bettencourt MS. Longitudinal melanonychia. Arch Dermatol 2003;139:1209-14. [PMID:12975169]23. Dalle S, Ronger-Savle S, Cicale L et al. A blue-gray subungual discoloration. Arch Dermatol 2007;143:937-42. [PMID:17638741]24. Causeret AS, Skowron F, Viallard AM et al. Subungual blue nevus. J Am Acad Dermatol 2003;49:310-2. [PMID:12894085]25. Moulonguet-Michau I, Abimelec P. Nail unit blue melanocyte nevi: 2 case reports. Ann Dermatol Venereol 2004;131:984-6. [PMID:15602387]26. Naylor EM, Ruben BS, Robinson-Bostom L et al. Subungual blue nevus with combined phenotypic features. J Am Acad Dermatol 2008;58:1021-4. [PMID:18485984]

Acquired blue nevus of the nail bed

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