Clinical and histopathological studies on spotted grouped pigmented nevi with special reference to eccrine-centered nevus.

Clinical and histopathological studies on 16 cases of spotted grouped pigmented nevus resulted in this disease being classified into at least three types. Characteristic findings of each type are described in this paper, in particular that nevus cell proliferation, a finding common to each type, is closely related pathogenetically to skin appendages, especially with eccrine sweat ducts. The eccrine-centered nevus characterized by Mishima corresponds to the third type, according to the present author's classification. The similar characteristic histopathological finding was also observed in a specimen taken from a black papule in a case of giant pigmented nevus with disseminated pigment cell nevi. We would like to consider that the cells of eccrine-centered nevus are derived from nevoblasts present in the walls of sweat ducts.     

Nevoid follicular mucinosis: a new type of hair follicle nevus

Follicular mucinosis represents a term for a histopathologic reaction pattern in follicular epithelium. It is a characteristic of alopecia mucinosa. However, it may also occur in a variety of unrelated conditions. Epidermal nevi are considered to be hamartomatous disorders and they can show a predominant component of non‐organoid (keratinocytes) and/or organoid nevi. All the cases of epidermal nevi described with mucin deposits until now are reported as mucinous nevus or mucinous eccrine nevus; in the first type of disorder, diffuse mucin deposition is only seen in the papillary dermis, and in the second type, the mucin is found around the proliferation of eccrine structures. We believe this is the first reported case of epidermal nevus along Blaschko's lines exhibiting typical microscopic findings of mucinosis exclusively distributed inside the follicular epithelia.     

Pure apocrine nevus: a report of 4 cases

Apocrine nevus is a rare tumor composed of increased mature apocrine glands and ductal structures within a fibrous stroma, located predominantly in the reticular dermis. They have been reported in association with apocrine carcinoma, extramammary Paget disease, and syringocystadenoma papilliferum; less commonly a pure apocrine nevus is identified, unassociated with another apocrine proliferation. Clinically apocrine nevi may appear as solitary or multiple nodules or plaques on the scalp, presternal skin, though they are seen most commonly in the axillae. We describe 4 cases of pure apocrine nevus, all of which appeared clinically as painless or mildly tender skin-colored axillary masses, 2 of which were bilateral. In each case, the lesions appeared in adulthood, and patients denied knowledge of congenital or childhood presence. Patients denied pruritis, discharge, bleeding, or antecedent trauma. Grossly, the specimens consisted of subcutaneous, multicystic ill-defined nodules. Biopsy showed prominent apocrine glands composed of irregularly columnar luminal cells with eosinophilic cytoplasm arranged in a somewhat organoid pattern filling the reticular dermis and extending into the subcutaneous adipose tissue. The glandular luminal cells displayed decapitation secretion. There was a paucity of pilosebaceous units. In one case, the overlying epidermis was papillomatous. The deepest portion of one specimen had lactational change simulating a lactational adenoma. No atypia was seen in either the glandular structures or the stroma. The adjacent sebaceous and eccrine structures were normal. The histologic features and immunohistochemical profile in relation to other apocrine lesions will be reviewed.     

Acantholytic dyskeratotic epidermal nevus with eccrine differentiation: a case report and review of literature

Terminology regarding classification of benign lesions with prominent eccrine differentiation can be confusing as these lesions can have overlapping clinical and histologic characteristics. In this report, we examine a case and review of the literature to suggest that these entities may be better classified as a spectrum of benign lesions with overlapping features rather than distinct entities. We describe a case of an acantholytic dyskeratotic epidermal nevus with eccrine differentiation on the back of a 2-year-old patient. We then discuss the classic clinical and histologic presentations of eccrine nevi and epidermal nevi with eccrine differentiation as they relate to each other and to our case.     

Widespread porokeratotic eccrine ostial and dermal duct nevus along Blaschko lines

Porokeratotic eccrine ostial and dermal duct nevus is a congenital hamartoma of possible eccrine origin with no malignant potential. It is usually localized at the extremity of a single limb, while wider systematized distribution has rarely been documented. A child with an unusually widespread nevus following Blaschko lines is reported. The disorder had a striking presentation in the form of a systematized linear epidermal nevus composed of multiple tiny filiform keratotic spines, which histologically corresponded to columns of porokeratosis. Serial histopathologic sections of a 4-mm punch biopsy specimen barely demonstrated an anatomic relationship between the porokeratotic columns and the underlying acrosyringeal duct. This report provides further evidence of porokeratotic eccrine ostial and dermal duct nevus being distributed along Blaschko lines, thus confirming it is a peculiar epidermal nevus due to a mosaic cutaneous condition.     

Mechanism of recurrence of pigmented nevi following dermabrasion.

A study was made of pigment freckles which recur after skin abrasion of spotted grouped pigmented nevi, according to the lapse of time, chiefly by means of the fluorescence method of Falck and Hillarp. The mechanism of recurrence is summarized as follows. Nearly simultaneously with the epidermal regeneration, dendritic melanin-producing cells derived from hair follicles and eccrine sweat ducts appear in the basal and prickle-cell layers of epidermis. These cells then create junction activity in the basal layer of epidermis, in the hair follicles and in the eccrine sweat duct walls. Finally, these nevus cells drop off into the underlying layer of scar tissue along the epidermal appendages. The dendritic melanin-producing cells seen in the early regenerative pigment freckles were thought to be incompletely differentiated nevus cells in the pre-stage of junction nevus formation. Appearance of dendritic melanin-producing cells and formation of junction activity in the eccrine sweat duct walls suggest the following possibilities. (1) In the cases of spotted grouped pigmented nevus which we studied, nevus cell proliferation also occurred eccrine-centrically on pathogenesis. (2) An important role is played by the eccrine sweat ducts in the recurrence of ordinary pigmented nevi after incomplete removal. (3) Eccrine-centered nevus cells are derived from nevoblasts in the eccrine sweat duct walls.     

汗孔角化性小汗腺孔和真皮导管痣

报告1例汗孔角化性小汗腺孔和真皮导管痣。患儿男,7岁。因手足和左膝关节内侧角化性丘疹和黑头粉刺样丘疹7年就诊。部分丘疹呈线状或带状排列（主要位于手足侧缘）。组织病理检查可见多个黑头粉刺样的表皮凹陷,内有角化不全柱。有些角化不全柱内可见扭曲的末端小汗腺导管穿过。角化不全柱的底部颗粒层变薄或消失,角质形成细胞空泡化,并可见角化不良细胞。角化不全柱下方的真皮内可见小汗腺导管。     

Composite Extrarenal Rhabdoid Tumor of the Skin: Cytology, Morphology, Electron Microscopy and Special Stain Findings

We present the case of a 27 year‐old female with a linear array of brown keratotic papules with a raised nodule within, located in the right mid upper inner thigh. A biopsy of the nodule showed a superficially invasive squamous cell carcinoma. Subsequent excision of the entire lesion showed an epidermal nevus without residual carcinoma. Squamous cell carcinomas developing within an epidermal nevus constitute an unusual association, mostly occurring in long standing lesions of elderly patients. Other epithelial neoplasms described arising within epidermal nevi include basal cell carcinomas, malignant eccrine tumors and keratoacanthomas. Although our patient did not have an identifiable epidermal nevus syndrome, the presence of a squamous cell carcinoma within an epidermal nevus in a young person suggests increased susceptibility to tumor development. Moreover, chromosomal aberrations have been described in epidermal nevi, including chromosomal breakage and variegated translocation mosaicism. We suggest that the presence of an epidermal nevus should alert the clinician for the potential development of a malignant neoplasm within it, including squamous cell carcinoma, even in the absence of an identifiable hamartoma‐neoplasm syndrome.     

Porokeratotic eccrine ostial and dermal duct nevus

A case of porokeratotic eccrine ostial and dermal duct nevus (PEODDN) affecting all 4 extremities is described. Clinically, palmo-plantar lesions resembled those of nevus comedonicus and the remaining lesions those of linear verrucous epidermal nevus. Histologically, all lesions were identical with cornoid lamellae in the eccrine ostia and epidermal ducts.     

The Spectrum of Epidermal Nevi: A Case of Verrucous Epidermal Nevus Contiguous with Nevus Sebaceus

During the normal development of skin, pluripotential cells give rise to keratinocytes, sebaceous glands, hair follicles, apocrine glands, and eccrine glands. In epidermal nevi, these components emerge in an abnormal mixture within a circumscribed site. Many authors have categorized epidermal nevi based on their predominant component; however, there is often notable overlap that occurs within a single area or within contiguous areas. We report a verrucous epidermal nevus contiguous to a nevus sebaceus of Jadassohn. The categories of epidermal nevi are somewhat artificial. Our case supports the view that epidermal nevi have a spectrum of manifestations, including verrucous epidermal nevi and nevus sebaceus of Jadassohn.     

Solitary eccrine syringofibroadenoma with prominent plasma cell infiltration

Eccrine syringofibroadenoma (ESFA) is a rare, benign, adnexal neoplasm thought to be eccrine ductal differentiation displaying variable clinical findings and characteristic histological features. It usually occurs as a solitary nodule on the extremities of an elderly person. Histological findings typically show a proliferation of anastomosing strands, cords, and columns of monomorphous epithelial cells that harbor eccrine duct formations embedded in a fibrovascular stroma. Acrosyringial nevus, though usually regarded as an identical lesion, is sometimes regarded as a different entity showing prominent plasma cell infiltration. We report two cases of solitary ESFA with prominent plasma cell infiltration. Clinicopathological features of both cases suggest that acrosyringeal nevus and ESFA may be of the same disease entity. Prominent plasma cell infiltration may be just one of the common histological features of ESFA.     

Sclerosing nevus with pseudomelanomatous features

Background: Among the pigmented lesions with a central area of scar, we found a group of cases histologically characterized by striking architectural alteration of the melanocytic component, but with no cytological atypia and mitotically quiescent. The aim of the current study was to assess the biological nature of such lesions. Methods: We selected 19 of these melanocytic neoplasms that had the following characteristics: (a) a clinically evident whitish central area suggestive of regression (with no history of a previous surgical procedure or trauma), (b) histological features of fibrous scar‐like tissue at the center of the lesion, (c) the presence of large, confluent and unusually shaped melanocytic nests at the dermoepidermal junction and in the dermis, (d) a pagetoid spread of melanocytes above the epidermal basal layer and (e) remnants of nevus tissue at the border of the scar. The lesions showed no evidence of cytological atypia, expansive nodules of melanocytes, significant numbers of mitoses or cellular necrosis. Results: All the cases have been followed up and none have recurred or metastasized. Histologically, these neoplasms have important similarities with the so‐called recurrent nevus, nevi on lichen sclerosus and nevi developed during or following cutaneous inflammatory and sclerosing processes. The origin of the scar in each case was obscure but was probably related to minor unnoticed trauma or to chronic friction on a nevus. In few cases, the fibrosis was probably the result of partial regression of the nevus or a sequel to folliculitis. The pseudomelanomatous features appear to be related to the presence of the scar, as already reported for nevi that are involved in fibrotic or scarring processes. In our study, the nevi involved in the fibrotic process were congenital nevi and common or dysplastic nevi. One case was a Spitz nevus. Conclusions: From our data we concluded that, despite their worrisome clinical and histological aspect, the lesions described in this case series were most probably benign melanocytic nevi, involved by a fibrotic process combined with pseudomelanomatous proliferation. The lack of cytological atypia, mitoses and expansive nodules allowed us to differentiate these lesions from regressing melanomas.     

Amelanotic blue nevus: a variant of blue nevus.

Blue nevi are typically heavily melanized. We report a variant of blue nevus that is minimally pigmented. Of the 1,358 blue nevi seen in our laboratory during the last 6 years, 38 (2.7%) were selected that had scant or absent melanin. We refer to these blue nevi as the amelanotic type. Approximately half of the cases in clinical diagnosis were nevus of some type, whereas other differential diagnoses were basal cell carcinoma, dermatofibroma, and lesion. Histologically all specimens were characterized by the spindle-shaped cells seen in blue nevi, but with very little or no obvious melanin. Some lesions were markedly cellular, resembling the features of cellular blue nevus. No hemosiderin was identified on Perls' stain, whereas Fontana-Masson stain was variably positive. Usually there was fibrous stroma. In most cases, the histologic differential diagnosis was dermatofibroma. Other histologic differential diagnoses included amelanotic and/or spindle cell melanoma, dermal Spitz nevus, neurofibroma, and scar. There was no pleomorphism or increased mitotic activity. Evidence of epidermal melanocytic hyperplasia was seen in two cases. Furthermore, the lesions had been present for many years without evidence of recent change. Immunohistochemistry showed all cases to be strongly positive with anti Mel-5 antibody, but only weakly positive or negative with anti S-100 and HMB-45 antibodies. We would like dermatologists and pathologists to be aware of this unusual and uncommon entity.     

Eccrine syringofibroadenoma (Mascaro): an ultrastructural study

To confirm the eccrine acrosyringeal differentiation of eccrine syringofibroadenoma (ESFA) and to elucidate the histogenesis of its angiofibrotic stroma, a case of ESFA from a 45-year-old man was examined by light and electron microscopy. Histologically, the parenchyma featured anastomosing, slender epithelial cords containing small cuboidal cells and occasional duct-like structures. The stroma had increased numbers of mast cells, increased capillaries with swollen endothelial cells, and prominent fibrosis. Ultrastructurally, the following findings were characteristic of ESFA: a) abundant glycogen particles in epithelial cells, b) numerous intracytoplasmic and extracellular spaces lined with microvilli, c) intraepithelial duct formation, consisting of microvilli, vesicles, rod-shaped dense bodies, multivesicular dense bodies, and peripheral network of tonofilaments, and d) large numbers of mast cells, closely associated with fibroblasts, surrounding increased numbers of capillaries containing swollen endothelial cells. These ultrastructural features support the acrosyringeal differentiation of ESFA. We hypothesize that mast cell hyperplasia and degranulation may play an important role in the formation of the angiofibrotic stroma.     

皮脂腺痣并发毛母细胞瘤

报告1例皮脂腺痣并发毛母细胞瘤。患者女,39岁。出生即发现右侧耳周芝麻至粟粒大褐色丘疹。皮肤科检查:右侧耳前部可见条带状斑块,呈蜡样光泽,其上有结节,局部糜烂及结痂;右侧耳后部可见密集分布的蜡黄或棕褐色角化性丘疹或斑块,边界清楚。皮损组织病理检查:表皮突延伸,区域表皮长出多个原始的毛乳头样结构,周边细胞呈栅栏状排列;真皮层可见结节状的毛母细胞瘤以及大量皮脂腺结构,下方无毛囊。诊断:皮脂腺痣并发毛母细胞瘤。治疗:予手术切除。     

Meyerson痣6例临床及病理分析

目的:探讨Meyerson痣临床及组织病理特征。方法:回顾性分析2015年1月至2020年1月第四军医大学西京皮肤医院确诊的6例Meyerson痣患者临床及病理资料。结果:6例患者中,男3例,女3例,年龄7个月至28岁,中位年龄10.5岁。3例皮损位于四肢,3例位于躯干。4例发生于先天性色素痣,2例发生于获得性色素痣。...     

Behavior of pigment cells on lesions of the pigmented venus with vitiligo.

When vitiligo occurred on lesions of the pigmented nevus, the behavior of pigment cells in this nevus was investigated. Three cases of giant hairy nevi, seven cases of moles, three cases of Mongolian spots and eleven specimens in nine cases of halo nevi were used. Giant hairy nevi combining with vitiligo showed intensive decreases in nevus cells, particularly superficial A and B-type nevus cells. The epidermal dopa-positive melanocytes and melanin granules in the epidermis decreased, but still remained. On the other hand, moles in vitiligo showed an almost complete disappearance of epidermal dopa-positive melanocytes and melanin granules in the epidermis; nevus cells in the dermis decreased only slightly. Mongolian spots with vitiligo showed an epidermis similar to vitiligo, but the dermal melanocytes were hardly changed. Halo nevi exhibited an intensive decrease and degeneration of nevus cells and marked lymphocytic infiltration. Some of them showed disappearance of epidermal dopa-positive melanocytes and melanin granules in the epidermis. The characteristic findings of vitiliginous skin are mostly restricted to epidermis. In contrast, however, it is interesting to note that, on the lesions of nevocellular nevi with vitiligo, the dermis also exhibited some decrease and degeneration of nevus cells and lymphocytic infiltration.     

Eccrine syringofibroadenoma (Mascaró). An acrosyringeal hamartoma

Two patients with eccrine syringofibroadenomas were studied. The first patient had a 3-year history of asymptomatic, unilateral, linear, moist mosaic plaques of the lower part of the left leg and foot; the second patient had a solitary papule on the back. Histologically, both tumors exhibited superficial elongated strands of eccrine ductal epithelium containing occasional lumina lined by an eosinophilic cuticle. The stroma was loose, myxoid, and fibrovascular. The secretory portions of the eccrine glands were ectatic in the first patient but were not seen in the second patient. We believe these lesions represent acrosyringeal hamartomas (nevi), although some authors interpret them as adenomas. The literature seems to indicate that lesions with similar histologic features may be solitary, multiple, or combined with other neoplasms; in other cases, the lesions may possibly represent an unusual morphologic expression of hidrotic ectodermal dysplasia.     

Reconstitution of the histologic characteristics of a giant congenital nevomelanocytic nevus employing the athymic mouse and a cultured skin substitute

This study addresses the development of an animal model for human giant congenital nevomelanocytic nevi (GCNN). Skin grafts were made from 1) non-involved split-thickness skin from a 12-month-old GCNN patient, 2) nevus split-thickness skin from the same GCNN patient, 3) nevus full-thickness skin, and 4) cadaveric human split-thickness skin. For groups 1) and 2), human epidermal and dermal cells were enzymatically isolated and expanded in tissue culture. Composite grafts were made by placing the cultured dermal cells into a collagen-glycosaminoglycan (GAG) matrix, followed by placement of the epidermal cells onto the opposite, laminated side of the matrix. All grafts were placed onto full-thickness wounds of athymic mice and biopsies were obtained from 6 to 38 weeks later for light microscopy including S-100 immunoperoxidase staining, and electron microscopy. The GCNN cultured skin mice (group 2) developed black, raised skin in the healed wounds. None of the group 1 mice developed lesions, grossly or histologically. All of the nevus full-thickness mice retained the nevus grossly. Histopathologic examination at 38 weeks of the black, raised plaques of group 2 demonstrated a reconstituted dermis similar to group 3. Nevus cells were larger and more epithelioid in the upper dermis, as seen with true GCNN. These nevomelanocytes were not seen in the dermis at 24 weeks, suggesting that the nevus cells migrated from the epidermal component of the cultured graft to the dermis during this time frame (24-38 weeks). The melanocyte identity of these cells was confirmed with S-100 immunoperoxidase staining and electron microscopy. These findings are unique to this composite cultured graft system. The ability to culture specific types of melanocytes and place them int skin substitutes on athymic mice provides a basis for the study of GCNN and melanocyte biology in vivo.     

Eccrine syringofibroadenoma in a patient with a burn scar ulcer

A 72-year-old woman with a burn scar on the calves of both legs developed an ulcer on her right heel, surrounded by multiple verrucous nodules and plaques. She had experienced similar verrucous lesions on both legs in the burn scar areas. Although the clinical diagnosis was Marjolin's ulcer, histologically the ulcer region showed thick fibrous tissue without any atypical epithelial cells. The verrucous lesions were consistent with the diagnosis of eccrine syringofibroadenoma (ESFA). Moreover, an ESFA-like growth pattern was seen in the elevated margin of the ulcer. Our findings suggest that these lesions developed as a result of reactive eccrine duct hyperplasia followed by skin tissue remodelling.