毛发上皮瘤的皮肤影像学特征分析

【摘要】 目的 比较毛发上皮瘤的反射式共聚焦显微镜（RCM）和皮肤镜特征与组织病理学特征。方法 2017年1月至2018年12月于武汉市第一医院皮肤科门诊收集经组织病理学确诊的毛发上皮瘤患者23例,采集RCM、皮肤镜图像,对比其与组织病理学特征的一致性。结果 23例中,男5例,女18例,年龄（39.5 ± 22.1）岁。组织病理特征：肿瘤界限清楚,周围有丰富的纤维基质;肿瘤团块为多数基底样细胞集合或相互交织的基底样细胞索,周边细胞呈栅栏样排列;肿瘤细胞不同程度地向毛乳头分化;可见不等数量的角囊肿。RCM特征：23例患者中8例可见真表皮交界处芽蕾样下延的条索状细胞,有栅栏样排列趋势;18例可见真皮层散在分布结节状似有分叶的瘤团,与周围组织无收缩间隙,呈扩大的低回声结构;16例瘤团周围有中高折光的无定形基质包绕;16例患者可见特征性的疑似原始分化毛乳头结构;20例可见清晰的角囊肿。皮肤镜特征：20例可清晰观察到珍珠白色、均质状结构,10例线状毛细血管扩张。结论 毛发上皮瘤的RCM特征与组织病理具有较高一致性,可作为辅助诊断及鉴别诊断的有效方法。     

Malignant transformation of multiple familial trichoepithelioma: case report and literature review

Patients with the autosomal-dominant form of multiple familial trichoepithelioma develop numerous tumours on the face, neck and upper trunk, beginning in childhood. Malignant transformation of such lesions is quite rare; only one case of "malignant trichoepithelioma" has been reported previously, inferring pilomatrix carcinoma on a histological observation. We report here the case of a patient who developed a malignant neoplasm in a long-standing trichoepithelioma lesion on her buttock. Histopathology revealed a transformation zone between the trichoepithelioma and a malignant tumour mass. This case also showed several features of a malignant neoplasm of trichoblastic origin.     

A poroid neoplasia arising close to a seborrheic keratosis and a trichoepithelioma.

A 69-year-old woman had a well-defined, slightly raised, brownish, keratotic plaque with an eccentric group of roughly circular, bluish, dome nodules on her right scapular area. Histological study revealed the presence of an eccrine poroma demonstrating features of eccrine poroma, hidroacanthoma simplex, and dermal duct tumor and arising in a lesion of seborrheic keratosis and a trichoepithelioma. In the eccrine poroma region, an area with malignant changes was evident. The findings in this case support the view of eccrine poroma as a spectrum of histological variants and the possibility of malignant transformation from a eccrine poroma towards porocarcinoma. The association with seborrheic keratosis is most probably coincidental, and the trichoepithelioma was probably due to induction of the tumoral stroma on adjacent follicular epithelia.     

Merkel cells are integral constituents of Desmoplastic trichoepithelioma: an immunohistochemical and electron microscopic study

The incidence of Merkel cells has previously been investigated in a number of inflammatory and tumorous lesions of the skin. Special attention was given to tumors with follicular differentiation. In the present study we examined the localization of Merkel cells in another adnexal tumor, the desmoplastic trichoepithelioma (n= 15), as well as in its main differential diagnosis, the morpheiform basal-cell carcinoma (n=30). Using immunohistochemical methods, we found Merkel cells as a stable constituent in desmoplastic trichoepitheliomas, but failed to detect them in morpheiform basal-cell carcinomas. These findings might therefore be an important tool in the sometimes very difficult but clinically imperative distinction between these two conditions. Furthermore, our study may be of interest in the discussion about the origin of desmoplastic trichoepitheliomas. High numbers of Merkel cells in desmoplastic trichoepitheliomas indicate a bulge-derived origin of this adnexal tumor, since high numbers of Merkel cells, especially in the bulge, were recently discovered. Although the significance of Merkel cell hyperplasia in desmoplastic trichoepithelioma is not presently understood, a regulatory role of the Merkel cell in growth and development of this adnexal tumor is suggested.     

Inguinal keratotic Basal cell carcinoma mimicking giant solitary trichoepithelioma

Keratotic basal cell carcinoma may not only clinically but also histologically share more or less the same features with giant solitary trichoepithelioma. It can be difficult to distinguish these two entities from each other, even for an experienced dermatopathologist. We present an unusual case of inguinal keratotic basal cell carcinoma mimicking giant solitary trichoepithelioma in a 56-year-old woman with a finger-like tumor of 20 years duration. The patient presented with an asymptomatic, skin colored, firm, nonulcerative, nodular lesion. Scanty mitotic activity and apoptotic cells were the histopathologic findings against basal cell carcinoma, whereas absence of papillary mesenchymal bodies, presence of peritumoral lacunae detected only around the solid areas, and accumulation of amyloid-like hyalinized material were the findings in favor of basal cell carcinoma. This case illustrates that keratotic basal cell carcinoma must be taken into account in the differential diagnosis of inguinally located solitary, polypoid masses, especially giant solitary trichoepithelioma.     

Desmoplastic trichoepithelioma: presentation of two cases

Trichoepithelioma is a benign neoformation with hair follicle differentiation that may clinically present in solitary, multiple or desmoplastic form. From a histopathological standpoint, it poses some diagnostic difficulties with basal cell carcinoma. We present two cases of desmoplastic trichoepithelioma, a rare adnexal tumor whose incidence is estimated at 2 per 10,000. Desmoplastic trichoepithelioma is a benign lesion, clinically and histologically similar to other dermatoses, and presents a true diagnostic challenge.     

Two cases of desmoplastic trichoepithelioma

Desmoplastic trichoepithelioma is a rare tumor that usually exhibits the distinct clinical features of a solitary granuloma annulare-like growth on the face. We experienced two cases of desmoplastic trichoepithelioma, one of which showed unusual clinical features and the other of which was a typical case. The first case was a 20-year-old female who presented with a five year history of a solitary yellowish nodule, 5 mm in diameter, centrally between the eyebrows. There was no central dimple or elevated border. The other case was a 40-year-old female who presented with a ten year history of a solitary nodule, 6 mm in diameter on her left cheek. The latter lesion had a typical depressed area in the center of the nodule with elevated borders and could be clinically diagnosed as desmoplastic trichoepithelioma. The histopathological examination revealed that both of them were desmoplastic trichoepithelioma. Histopathological comparison of the two specimens suggested that the clinical dimple in the center of the first tumor might be the result of stromal dystrophic changes induced by the tumor.     

Complex adnexal tumor of the primary epithelial germ with distinct patterns of superficial epithelioma with sebaceous differentiation, immature trichoepithelioma, and apocrine adenocarcinoma.

A 60-year-old man came for treatment of a sharply outlined erythematous plaque on the gluteal area (45 x 20 mm) of 20 years' duration. Eccentrically located on the plaque was a nodule, 20 mm in diameter. Histological study of the plaque showed a superficial platelike tumor with basaloid bland cytology and sebaceous gland differentiation. Histologic study of the nodule found an undifferentiated adenocarcinoma whose ductlike glandular structures opened to the skin surface and infiltrated the whole depth of the dermis. Study of other areas of the lesion detected two more neoplasms. A nodule of squamous cell carcinoma was found within the superficial band of the benign sebaceous tumor. The fourth neoplastic pattern consisted of epithelial islands composed of basaloid cells within a fibroblastic stroma. There was prominent palisading of epithelial cell nuclei at the periphery of the islands, which usually were surrounded by a sheath of mesenchymal cells. In this complex adnexal tumor of the primary epithelial germ, sebaceous and follicular differentiation both simulate neoplastic patterns recently described as separate entities: superficial epithelioma with sebaceous differentiation and immature trichoepithelioma. The undifferentiated adenocarcinoma may represent differentiation toward the third component of the germ, that is, the apocrine gland.     

Cutaneous lymphadenoma

Lymphoepithelial neoplasms are biphasic tumours that contain both epithelial and lymphoid components. This heterogeneous group includes benign cutaneous lymphadenoma (CL), malignant lymphoepithelioma-like carcinoma of the skin and dermal thymus. We present two cases of CL in male subjects of 14 and 64 years of age. The latter man had a history of multiple basal cell carcinomas (BCCs) and solar keratoses. Histological sections of both tumours revealed similar features of an invasive non-ulcerated tumour with a mixed architecture of BCC and trichoepithelioma. Immunocytochemical examination revealed a biphasic epithelial tumour of follicular differentiation, possibly a variant of trichoepithelioma or a BCC. Within the epithelial islands there was a heavy infiltration that was confirmed as CD3-positive T cells and S-100-positive dendritic cells by immunocytochemistry.     

Follicular stem cell marker PHLDA1 (TDAG51) is superior to cytokeratin-20 in differentiating between trichoepithelioma and basal cell carcinoma in small biopsy specimens

Background: Biopsies submitted to dermatopathologists are becoming increasingly smaller in size and thus the available diagnostic material is reduced. The distinction between trichoepithelioma and basal cell carcinoma remains challenging, particularly if tissue is limited. Merkel cells, which can be highlighted by means of cytokeratin‐20 (CK20) immunostaining, are used as a surrogate marker for the diagnosis of trichoepithelioma, as Merkel cells commonly colonize trichoepithelioma but are generally lacking in basal cell carcinomas. In the current study, we examined the expression of a recently characterized follicular stem cell marker, PHLDA1 (pleckstrin homology‐like domain, family A, member 1), also known as TDAG51 (T‐cell death‐associated gene 51). Methods: Using standard immunohistochemical techniques, we examined 19 trichoepitheliomas and 11 basal cell carcinomas for the expression of PHLDA1 and compared it with CK20 expression. Results: All 19 trichoepitheliomas were immunoreactive for PHLDA1 and all 11 basal cell carcinomas lacked PHLDA1 expression. Two of eleven basal cell carcinomas harbored CK20‐positive Merkel cells. Three trichoepitheliomas lacked secondary CK20‐positive cells. Conclusions: Our results suggest that PHLDA1 represents a practical and easily used tool that can be applied to the differentiation of trichoepithelioma and basal cell carcinoma in small biopsy specimens. Rather than searching for CK20‐positive Merkel cells, assessing PHLDA1 expression allows the differential diagnosis between trichoepithelioma and basal cell carcinoma to be solved at scanning magnification. Sellheyer K, Nelson P. Follicular stem cell marker PHLDA1 (TDAG51) is superior to cytokeratin‐20 in differentiating between trichoepithelioma and basal cell carcinoma in small biopsy specimens.     

角化型基底细胞癌与毛发上皮瘤细胞核DNA含量测定

利用图像分析技术对３０例角化型基底细胞癌及３０例毛发上皮瘤组织病理相似部分基底样细胞瘤块进行细胞核ＤＮＡ含量分析。结果显示角化型基底细胞部组有异倍体１６例，毛发上皮瘤组３０例均为二倍体。前者显示恶性生物学行为，而后者呈良性生物学行为。     

Congenital desmoplastic trichoepithelioma

Desmoplastic trichoepithelioma (DT) is a rare benign adnexal neoplasm considered to have follicular differentiation. It usually presents as an asymptomatic, firm, annular plaque with a raised border. The most common site of occurrence is the face, usually on the cheek. Females are more often affected than males and the age range of patients previously reported is 8-79 years. We present a case of congenital desmoplastic trichoepithelioma. A girl was born at term to a healthy mother after an uneventful pregnancy and was noted to have widespread erythematous plaques with milia-like lesions over the right scalp, face and neck, with some areas of atrophic scarring. Histology and immunohistochemistry of incisional biopsies of the lesions were consistent with a diagnosis of DT. To our knowledge, this is the first reported case of congenital DT.     

Desmoplastic trichoepithelioma with perineural involvement: a series of seven cases

Desmoplastic trichoepithelioma (DTE) is a benign follicular tumor occurring most commonly within facial skin of young and middle-aged women, morphologically characterized by a superficial dermal proliferation of basaloid cells growing in narrow strands embedded in a desmoplastic stroma associated with small keratinizing cysts. DTE must be distinguished from other benign epithelial proliferations such as syringoma, microcystic adnexal carcinoma and infiltrating basal cell carcinoma. Among morphological features useful in that distinction, perineural involvement is considered a feature indicative of malignancy. We present a series of seven DTEs with otherwise typical presentation and morphology, nevertheless showing epithelium present in the perineural spaces of adjacent small dermal nerves. Patients ranged in age from 14 to 66 years (mean 44 years). All seven tumors were restricted to dermis, showed strands of basaloid epithelium in desmoplastic stroma and contained CK20-positive cells. Additionally, five of five examined tumors displayed diffuse expression of p75 neurotrophin receptor. Five patients were followed up clinically (follow-up time range: 2 months-4 years). No tumor recurrence was observed in any of these patients. We postulate that perineural involvement is an unusual feature of DTE that should not be equated with malignancy or lead to unnecessary over-treatment.     

p75 Neurotrophin receptor differentiates between morphoeic basal cell carcinoma and desmoplastic trichoepithelioma: insights into the histogenesis of adnexal tumours based on embryology and hair follicle biology

Background Tumour development is frequently described in the basic pathology literature as a recapitulation of embryogenesis. However, a link between the embryology of the skin and the histogenesis of adnexal tumours has been largely overlooked. The low‐affinity p75 neurotrophin receptor (p75NTR) has a profound role in hair follicle biology. We therefore speculated that it is involved in the histogenesis of follicular adnexal tumours. One of the most challenging diagnoses in dermatopathology is differentiating morphoeic basal cell carcinoma from desmoplastic trichoepithelioma. Objectives To describe the expression pattern of p75NTR during cutaneous embryogenesis, in the adult hair follicle and in morphoeic basal cell carcinoma and desmoplastic trichoepithelioma. Methods Evaluation of the staining pattern for p75NTR was performed using standard immunohistochemical techniques. For comparison, we examined staining for cytokeratin 20 which highlights Merkel cells. Results All 17 desmoplastic trichoepitheliomas were immunoreactive with > 80% of the cells stained, whereas 12 of the 14 (86%) morphoeic basal cell carcinomas were p75NTR negative. In the two positive cases of morphoeic basal cell carcinoma < 30% of cells were labelled. In the late bulbous hair peg stage and in the postnatal anagen hair follicle p75NTR highlights the outer root sheath. Conclusions Our results support the classification of desmoplastic trichoepithelioma as a follicular hamartoma mimicking the outer root sheath. In contrast, the lack of p75NTR expression in morphoeic basal cell carcinoma favours a concept of this tumour as a more primitive follicular lesion with the characteristics of a carcinoma and not a hamartoma. We suggest including p75NTR as a tool in the differential diagnosis between morphoeic basal cell carcinoma and desmoplastic trichoepithelioma.     

PHLDA1 (TDAG51) is a follicular stem cell marker and differentiates between morphoeic basal cell carcinoma and desmoplastic trichoepithelioma

Background Morphoeic basal cell carcinoma (BCC) and desmoplastic trichoepithelioma can often be difficult to differentiate on routine sections and few reliable immunohistochemical markers are currently available. Recent cDNA microarray studies revealed the pleckstrin homology‐like domain, family A, member 1 protein (PHLDA1) as a highly reliable marker of the hair follicle stem cells. Given the differentiation of trichoepithelioma along the follicular lineage and the proposed role of PHLDA1 as a follicular stem cell marker, we examined the staining pattern of PHLDA1 in the desmoplastic variant of trichoepithelioma and in its differential diagnostic conundrum, morphoeic BCC. Objectives To describe the expression pattern of PHLDA1 in morphoeic BCC and desmoplastic trichoepithelioma. Methods Evaluation of the staining pattern for PHLDA1 was performed using standard immunohistochemical techniques. For comparison reasons, we analysed staining for PHLDA1 in normal skin structures with particular reference to the hair follicle. Results With the exception of one case, all 16 desmoplastic trichoepitheliomas were immunoreactive with more than 80% of the cells stained, whereas all 14 morphoeic BCCs were PHLDA1‐negative with the exception of ulcerated tumours. In the latter, the tumour islands close to the ulcer were PHLDA1‐positive whereas the deeper located tumour portions remained immunonegative. PHLDA 1 was prominently expressed in the hair follicle bulge of terminal and vellus hair follicles. Conclusions The hair follicle bulge marker PHLDA1 differentiates between desmoplastic trichoepitheliomas and nonulcerated examples of morphoeic BCCs. We suggest incorporating PHLDA1 in the diagnostic work‐up of difficult to differentiate basaloid tumours.     

Immunohistochemical and ultrastructural observations of desmoplastic trichoepithelioma with a special reference to a morphological comparison with normal apocrine acrosyringeum

BACKGROUND: Desmoplastic trichoepithelioma is a benign neoplasm considered to have follicular differentiation. Its sweat gland- or sebaceous-lines of differentiation have been also reported. There have been, however, only a few reports regarding extensive immunohistochemical and ultrastructural investigations of this neoplasm. METHODS: Histopathological and immunohistochemical studies were performed on three cases of desmoplastic trichoepithelioma, comparing it with normal skin. One of these cases was ultrastructurally investigated. RESULTS: The cord-like basaloid nests were reacted with the anti-cytokeratin (CK)1/5/10/14, -CK5/8, -CK14 and -CK15 antibodies, but not with the anti-CK6 antibody. Similar findings were observed in the outer layers of the normal follicular outer root sheath. Basaloid cell nests in one case, which showed ductal structures in the nests, also expressed CK7, CK8/18 and CK19. These keratins were also detected in the normal sweat glands. In addition, CK8/18 and CK19 were expressed in the basal cells of the outer root sheath. Keratinous cysts had inner reactions with the anti-CK10/11 and -CK6 antibodies, and outer reactions with anti-CK5/8 and -CK14 antibodies. Ultrastructurally, the cells in the cord-like nests were basically immature and basaloid in appearance. A few cells contained Odland bodies, which were also observed in the normal apocrine acrosyringeum. The ductal structure was lined by the cells which bore numerous microvilli in the luminal surface. CONCLUSION: The cells in desmoplastic trichoepithelioma are suggested to be in close association with the basal cells in the outer root sheath, which can differentiate into various parts of the folliculosebaceous apocrine unit.     

Desmoplastic trichoepithelioma

A 20-year-old male presented with a 4 year history of a solitary nodule, 8 mm in diameter on the left temple. It was covered by normal skin, with a central depression and elevated borders. Histopathology showed numerous born cysts amidst nests and strands of basaloid cells surrounded by a dense fibrous stroma. The clinical and histopathological features were characteristic of desmoplastic trichoepithelioma.     

Desmoplastic trichoepithelioma nosology. Reappraisal about a case developed on a varicella scar

We report the case of a 51-year-old woman who presented with a progressive elevation of the border of an old varicella scar. The lesion which was clinically diagnosed as a basal cell carcinoma turned out to be a typical desmoplastic trichoepithelioma. The development of desmoplastic trichoepithelioma in an area of scarring has not been previously reported. The nosology of this tumor is discussed with particular emphasis on its possible relationship to morphoeic basal cell carcinoma, thus questioning it as a true tumor sui generis.     

Congenital non-familial unilateral basaloid follicular hamartoma

Basaloid follicular hamartoma is not a well-recognized clinical entity and has often been diagnosed as trichoepithelioma or basal cell carcinoma. It is a unique benign follicular tumour which comprises a variety of clinical manifestations. We present the case of a 24-year-old male with unilateral basaloid follicular hamartoma present at birth and later misdiagnosed as basal cell carcinoma. Histological features of basaloid follicular hamartoma are not always diagnostic and clinico-pathological correlation is particularly important to distinguish this benign hamartoma from other basaloid tumours including basal cell carcinoma. Continuous follow-up of our patient did not reveal any clinical or histological malignant transformation.