[A case of trichoblastoma of the auricular cavity and review of the literature].

Trichoblastoma（TB） is a rare germ cell skin adnexal tumor of the hair, and it is a rare follicular tumor of the skin that differentiates from the hair germ epithelium and is often regarded as a benign skin tumorHowever, it is poorly confined and has a local infiltrative growth pattern. tb occurs in the head and neck region, especially in the face, and presents clinically as a slow growing, well-defined and elevated nodule. TB is routinely treated surgically. Due to the lack of universally accepted treatment guidelines or protocols, the recurrence rate after surgery is high, which makes clinical cure more difficult. In this study, a 65-year-old female patient was found to have a swelling with recurrent rupture and pus flow from the right external auditory canal opening and the auricular cavity. After initial misdiagnosis as otitis externa, she was treated with conventional anti-infective therapy, but her symptoms did not resolve and gradually worsened before coming to our hospital. The condition presented in this case is relativelyrare,therepre,timely and accurate diagnosis and treatment are crucial for prognosis improvement of such diseases.

Fusion-driven cutaneous and superficial mesenchymal and adnexal tumors-A clinicopathologic and molecular study of 15 cases, including a novel case of ACTB::ZMIZ2-rearranged adnexal carcinoma.

BACKGROUND: While the list of fusion-driven soft tissue neoplasms is expanding rapidly, their importance among cutaneous and superficial mesenchymal and adnexal neoplasms remains poorly understood. This challenge is especially evident in cases with ambiguous histopathology that are difficult to classify based on morphology. AIMS: Our goal was to investigate the benefits of next-generation sequencing in diagnosing complex cutaneous neoplasms. MATERIALS & METHODS: Departmental archives were searched for fusion-driven cutaneous neoplasms. Slides were retrieved and clinical information including follow-up was obtained. RESULTS: Fifteen cases occurred in eight female and seven male patients, with a median age of 26 years (range: 1-83) at diagnosis. Tumors involved the extremities (9), scalp (5), and head and neck (1). Predominant features included myoepithelial (5), nested spindled with clear cytoplasm (2), atypical adnexal/squamoid (2), small round blue cell (2), cellular spindled (3), and fibrohistiocytic morphology (1). Most frequently encountered fusions involved EWSR1 (6) fused to ERG (1), FLI1 (1), CREB1 (2), CREM (1), PBX3 (1), followed by PLAG1 (4) with LIFR (2), TRPS1 (1) and CHCHD7. Additional fusions encountered were YAP1::NUTM1, EML4::ALK, SS18::SSX1 (2), and a novel fusion: ACTB::ZMIZ2. Integration of histologic features and molecular findings led to final diagnoses of primary cutaneous Ewing sarcoma (2), soft tissue myoepithelioma (4), cutaneous syncytial myoepithelioma (1), cutaneous adnexal carcinoma (1), porocarcinoma (1), inflammatory myofibroblastic tumor (1), synovial sarcoma (2), clear cell sarcoma (2), and angiomatoid fibrous histiocytoma (1). DISCUSSION AND CONCLUSION: Our results show that fusion testing can be a helpful diagnostic tool, especially in cases with unusual or uncommon morphology in superficial sites. Furthermore, it can allow for the identification of potential therapeutic targets in some instances.

Five-year pattern of adnexal tumors of the skin in Ethiopia.

BACKGROUND: Adnexal tumors of the skin are rare neoplasms that encompass a wide range of dermatologic entities. Here, we investigated the pattern of adnexal tumors of the skin in the All African Leprosy and Tuberculosis Rehabilitation and Training Center (ALERT) hospital retrospectively. METHODS: A hospital-based retrospective study was conducted at ALERT from histopathology records in the Armauer Hansen Research Institute (AHRI) pathology laboratory of patients diagnosed with any of the skin adnexal tumors during the time period January 2017 to December 2021. A structured data extraction sheet was used. Data entry was done using EpiData 4.6.0.6. Data were analyzed using SPSS version 25. RESULT: A total of 146 skin adnexal tumors were identified making the magnitude 2.8% of total biopsies. The 3rd decade of life was found to be the most common age group. Male-to-female ratio was 1 : 1.05. Majority of the tumors were benign (82.2%) and had sweat gland differentiation at 48.6%. Poroma (10.9%) was the most frequent tumor, whereas porocarcinoma (6.8%) made up the most frequent malignant tumor. The most common site was the head and neck region (48.6%). Only 21.2% of the tumors were correctly identified clinically. CONCLUSION: The magnitude of skin adnexal tumors is found to be slightly higher than other similar studies which could be because it was carried out in the largest dermatologic center in the country. The most common skin adnexal tumors identified, their localizations, and lines of differentiation are all in line with other studies. Histopathologic examination is mandatory for the accurate diagnosis of these tumors.

Periocular Microcystic Adnexal Carcinoma: A Case Report and a Major Review.

PURPOSE: To describe a patient with periocular microcystic adnexal carcinoma (MAC) and to review the clinical presentation, systemic work-up, histopathologic features, and outcome of all previously reported periocular MAC. METHODS: A major literature review. PubMed/MEDLINE and Google Scholar databases were searched for all well-documented cases of periocular MAC. RESULTS: The final analysis yielded 93 patients with MAC, 48 (52%) females, 39 (42%) males, and 6 with sex not specified (6%) with an average age of 56 years (range 3 days-95 years). Most tumors were localized to the eyebrow (26/93, 28%) and lower eyelid (20/93, 22%). Of patients with known information, MAC most commonly presented as a nodule (37/68, 54%) or plaque (20/68, 29%) with poorly-defined margins (20/51, 39%) and distortion of eyelid margin (13/51, 25%). Orbital involvement at any point of the disease course was seen in 20 of 93 (22%) patients. An accurate histopathologic diagnosis on initial biopsy was made in 25 of 70 (36%) cases. Initial management included surgical excision (47/93, 51%), Mohs micrographic surgery (17/93, 18%), and excision with frozen section control of margins (8/93, 9%). Aggressive or recurrent MAC was managed with multimodal therapies, including adjuvant radiation (10/34, 29%). The average follow-up after the last treatment was 3 years (median 2, range 0.2-20 years). In total, 33 of 86 (38%) tumors recurred, and 6 of 87 (7%) metastasized. Disease-related mortality occurred in 3 of 79 (4%) of patients. CONCLUSIONS: Periocular MAC is frequently misdiagnosed on initial biopsy and has a tendency for recurrence and locally aggressive behavior, highlighting the importance of accurate timely diagnosis, and appropriate management.

A diagnostic challenge in an atypical variant of microcystic adnexal carcinoma mimicking ulcerative basal cell carcinoma: a case report and brief literature review.

Microcystic adnexal carcinoma (MAC) is a rare adnexal tumor with eccrine and pillar differentiations with a localized and aggressive nature, often misdiagnosed as other dermatoses. The most common clinical manifestations of MAC are yellowish or skin-colored papules, nodules, and plaques. However, in some rare cases an atypical manifestation such as ulceration that resembles malignancies such as basal cell carcinoma (BCC) can also occur. Diagnosis of MAC mainly relies on the aid of histopathology. Due to potential infiltration to other structures such as in perineural invasion, wide surgical excision or Mohs micrographic surgery is the preferred surgical option. We report the case of a 75-year-old male patient with ulcerative lesion on the forehead that clinically resembled BCC in addition to typical dermoscopic findings of BCC. However, histopathology confirmed a diagnosis of MAC, prompting physicians to be more aware of this condition when encountering chronic ulcerative lesions. After wide excision and a 1-year follow-up, the patient exhibited no signs of recurrences and will continue long-term follow-up.

PRAME immunostain expression in sebaceous lesions, cutaneous carcinomas and adnexal structures.

The use of immunostain for PRAME antigen is well established for cutaneous melanolocytic lesions. However, its staining in other cutaneous structures and lesions is under reported. This study assessed PRAME staining in a large cohort of normal skin tissue, sebaceous lesions, and cutaneous carcinomas to better delineate patterns of PRAME immunoreactivity. PRAME immunostaining was performed on sections of sebaceous lesions and tissue microarrays of basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs). Normal cutaneous adnexal structures were assessed on the sections of sebaceous lesions. For sebaceous lesions and non-lesional sebaceous glands, PRAME immunostaining was assessed for mature, germinative and sebocytes independently. A total of 193 sebaceous lesions, 64 BCCs and 35 SCCs were stained for PRAME immunostain. Staining pattern was predominantly cytoplasmic in normal apocrine glands, germinative sebocytes of sebaceous glands, and hair germs (p<0.001). Lesional sebocytes did not show different staining compared to normal sebaceous glands (p>0.05). Rare nuclear staining was observed in the normal epidermis (0.6%) and junctional melanocytes (4.1%). BCC, SCC and sebaceous carcinoma all showed low levels of PRAME immunoreactivity with variable proportions of cases demonstrating nuclear staining (BCC 59.4%, SCC 37.1%, sebaceous carcinoma 5.3%). PRAME immunostaining is positive in germinative sebocytes, various cutaneous structures and carcinomas. Nuclear staining, identical to melanoma, was observed in normal epidermis, junctional melanocytes, BCCs, SCCs, and sebaceous carcinomas. The pattern of PRAME staining in the skin must be recognised to avoid pitfalls in interpretating PRAME immunostain.

Does Immunohistochemistry Add to Morphology in Differentiating Trichoepithelioma, Desmoplastic Trichoepithelioma, Morpheaform Basal Cell Carcinoma, and Microcystic Adnexal Carcinoma?

BACKGROUND: The distinction among cutaneous basaloid neoplasms such as trichoepithelioma (TE), desmoplastic trichoepithelioma (DTE), morpheaform basal cell carcinoma (MBCC), and microcystic adnexal carcinoma (MAC) can be difficult, especially in superficial biopsies. As the treatment plan of each entity is different, accurate characterization is important for appropriate management. While TE and DTE are benign neoplasms with indolent behavior, MBCC and MAC are typically locally aggressive. The expression of several recently described immunohistochemical (IHC) markers, including p40, IMP3, and ProEx C, has not been adequately established in cutaneous neoplasms. We explored the potential utility of a broad IHC panel, including previously reported and novel markers to differentiate TE, DTE, MBCC, and MAC. DESIGN: A total of 35 archival cases [TE (n=14), DTE (n=9), MBCC (n=6), and MAC (n=6)] were stained with 9 IHC markers: p40, IMP3, ProEx C, p16, CK20, Ki-67, androgen receptor, D2-40, and beta-catenin. Tumors with >5% immunoreactivity were scored as positive. The intensity was scored on a scale from 1+ to 3+. The pattern of positivity- nuclear, cytoplasmic, membranous, or in combination; peripheral or central distribution with lesion was also recorded. RESULTS: CK20 (in contrast to prior studies) and IMP3 were negative in all cases. Likewise, with the exception of one case of TE, androgen receptor showed no immunoreactivity in all categories. No significant difference was observed in the expression of beta-catenin, p16, ProEx C, and p40 among the four groups of cutaneous neoplasms. The mean Ki-67 labeling index for MBCC (8%) was slightly higher than DTE (3%). Interestingly, the proliferation index for TE (15%) was significantly higher than that of MBCC. All six cases of MAC and 36% of TEs expressed D2-40; neither the MBCC nor DE cases showed D2-40immunoreactivity. Also, we confirmed the previously published observation of scattered CK20 positive Merkel cells in the epidermis of all cases of DTE; whereas, no Merkel cells were identified in MBCC and MAC cases. CONCLUSIONS: Except Ki-67, our IHC panel showed no significant added diagnostic utility of IHC in discriminating among TE, DTE, MBCC, and MAC. Among the four cutaneous neoplasms, DTE and MBCC show a small but discernible difference in Ki-67.

The Utility of Myoepithelial Cell Layer Identification in Adnexal Carcinomas.

ABSTRACT: The distinction of metastatic carcinomas to the skin (MCS) from cutaneous adnexal carcinomas can pose a significant diagnostic challenge. The differentiation between (MCS) from a primary cutaneous adnexal tumor is one of the most difficult tasks in the field of dermatopathology, and immunohistochemistry has only been partially helpful in solving this problem. In routine diagnostic surgical pathology, it is essential to identify the myoepithelial cell layer by immunohistochemistry to distinguish between an in situ and invasive breast carcinomas and when establishing the presence of microinvasion. The purpose of this study was to evaluate the role of myoepithelial cell layer expression in difficult cases of cutaneous adnexal carcinomas in which histologically it was challenging to separate them from MCS. We studied 38 adnexal carcinomas and evaluated them for myoepithelial markers to confirm the primary nature of the neoplasm. The used markers to search for myoepithelial cell layer retention included calponin, p63, and smooth muscle actin. Of the 38 cases, we found that 13 cases showed myoepithelial layer retention, confirming the primary cutaneous origin of the neoplastic process. The results of our study suggest that the presence of an identifiable retention of the myoepithelial cell layer in adnexal carcinomas could be a useful adjunct observation in the diagnosis of primary adnexal carcinomas, especially in the clinical setting of a questionable primary adnexal versus metastatic neoplasm.

Impact of expert pathology review in skin adnexal carcinoma diagnosis: Analysis of 2573 patients from the French CARADERM network.

PURPOSE: To prospectively assess the impact of expert pathological review of skin adnexal carcinoma diagnosis in France. METHODS: From 2014 to 2019, 2573 samples from patients with newly diagnosed or suspected skin adnexal carcinomas were reviewed prospectively by expert pathologists through the national CARADERM (CAncers RAres DERMatologiques) network. Changes in diagnosis between referral and expert review were analysed regarding their potential impact on patient care or prognosis. RESULTS: The samples comprised 2205 newly diagnosed adnexal carcinomas, 129 benign adnexal tumours, 136 basal cell carcinomas, 74 squamous cell carcinomas, six cutaneous metastases and 13 other malignancies. There were 930 (42%) sweat gland carcinomas, of which porocarcinoma (261; 11.8%), microcystic adnexal carcinoma (125; 5.7%) and hidradenocarcinoma (109; 4.9%) were the most frequent subtypes; 778 (35%) hair follicle carcinomas, 238 (11%) sebaceous carcinomas and 212 (10%) extramammary Paget diseases/mammary-like anogenital gland adenocarcinomas. A diagnostic change between referral and expert review occurred in 503 (21.3%) patients, significantly higher for cases sent with a provisional diagnosis seeking an expert second opinion (45.7%) than for cases sent with a formal diagnosis (2.8%) (p < .0001). Sweat gland carcinomas were more prone to diagnostic discrepancies than other tumours (p < .0001), including 1.8% of patients with sweat gland carcinoma subtype misclassification with predicted clinical impact. Changes between benign and malignant conditions occurred in 117 samples (5% of patients). CONCLUSION: The study provides a unique description of the distribution of skin adnexal carcinomas and highlights the importance of expert review for these rare cancers. Optimal clinical management was impacted in a significant proportion of patients.

In Vivo Reflectance Confocal Microscopy of Adnexal Tumors: Evaluation of Trichoepithelioma, Sebaceoma, and Fibrofolliculoma.

ABSTRACT: Cutaneous adnexal tumors are benign and malignant neoplasms that undergo morphological differentiation into cutaneous adnexa, comprising pilosebaceous, eccrine, or apocrine units. Reflectance confocal microscopy is a noninvasive diagnostic method that enables in vivo visualization of tissues at a similar resolution as conventional histopathology. The use of this method in skin imaging over the past several years has improved dermatological diagnoses, potentiating its wide application, especially for benign and malignant skin tumors. We describe the use of reflectance confocal microscopy in cases of trichoepithelioma, sebaceoma, and fibrofolliculoma and correlate the resulting clinical, histopathological, and confocal microscopy images.

Current Diagnosis and Treatment Options for Cutaneous Adnexal Neoplasms with Apocrine and Eccrine Differentiation.

Adnexal tumors of the skin are a rare group of benign and malignant neoplasms that exhibit morphological differentiation toward one or more of the adnexal epithelium types present in normal skin. Tumors deriving from apocrine or eccrine glands are highly heterogeneous and represent various histological entities. Macroscopic and dermatoscopic features of these tumors are unspecific; therefore, a specialized pathological examination is required to correctly diagnose patients. Limited treatment guidelines of adnexal tumor cases are available; thus, therapy is still challenging. Patients should be referred to high-volume skin cancer centers to receive an appropriate multidisciplinary treatment, affecting their outcome. The purpose of this review is to summarize currently available data on pathogenesis, diagnosis, and treatment approach for apocrine and eccrine tumors.

Skin tumors in xeroderma pigmentosum: Evaluation of a large series and a literature review.

BACKGROUND: Xeroderma pigmentosum (XP) is a rare genodermatosis with a lifelong propensity to develop malignant skin tumors. METHODS: In this retrospective study, 24 XP patients were evaluated with regard to frequency and clinicopathological features of benign and malignant skin tumors. RESULTS: Seventeen patients had at least one malignant skin tumor diagnosed: basal cell carcinoma (BCC) in 13 patients (n = 72), basosquamous carcinoma in three patients (n = 4), squamous cell carcinoma in six patients (n = 13), keratoacanthoma in three patients (n = 15), and melanoma in six patients (n = 18). Most melanomas (n = 15) were in situ lesions. Several benign skin tumors were noted such as tricholemmoma (n = 1), trichoepithelioma (n = 1), trichoblastoma (n = 1), follicular infundibulum tumor (n = 1), keratoacanthoma-like follicular lesion (n = 1), adnexal tumors with folliculosebaceous (n = 1) and tricholemmal differentiation (n = 1), and neurofibroma (n = 1). Benign vascular proliferations including pyogenic granulomas (n = 8), widespread telangiectasias, and senile angioma-like lesions were also observed in 3, 5, and 5 patients, respectively. CONCLUSIONS: Similar to many reports, BCC was found to be the most common malignant skin tumor. The high prevalence of benign adnexal tumors of follicular differentiation, some of them showing mixed histopathological features and various vascular proliferations in our series raises the question of whether they indicate a formerly undescribed association with XP.

On-site cytological diagnosis of cylindroma: A case report.

A 70-year-old female presented with a swelling in the right auricle for 6 months. Rapid onsite stain and routine cytology revealed clusters of small, round to oval cells with hyperchromatic nuclei, inconspicuous nucleoli, and scant cytoplasm. The background had basement membrane type material and appeared dark magenta colored pinkish globular material. Hence a cytological diagnosis of skin adnexal tumor possibly cylindroma was made. The excision of the lesion also showed features of cylindroma. Rapid onsite staining and cytology of subcutaneous location of the tumor in the absence of primary salivary gland tumors may help to diagnose such rare cases.

Periocular skin cancer: Diagnosis and management.

The periocular region sees high rates of cancer compared to the rest of the body and can be affected by several unique tumors. Treatment typically involves surgical excision, although adjunctive therapies and prognosis vary depending on the diagnosis. Basal cell carcinoma (BCC) is the most common malignancy affecting this region and should be excised promptly. This is followed by squamous cell carcinoma, which is often mistaken for BCC but is treated similarly. Melanoma is less common but more deadly, with relatively high rates of metastasis and death. Rare tumors that may be found in this region include sebaceous carcinoma, Merkel cell carcinoma, and microcystic adnexal carcinoma. While uncommon, these tumors are associated with poor outcomes and frequent recurrence. Recognition of periocular skin cancer is an important skill for primary care physicians, as prompt diagnosis and treatment can be sight or life-saving.

[Eccrine carcinoma: a diagnostic pitfall]. / Het eccrien carcinoom, een diagnostische valkuil.

BACKGROUND: The eccrine carcinoma is a rare form of skin adnexal malignancy, usually presenting as a locally invasive, solitary lesion in the head and neck region. Histopathologically and immunohistochemically, eccrine carcinomas are difficult to differentiate from cutaneous metastases of breast carcinomas. Unlike treatment of cutaneous metastasis, treatment of a solitary eccrine carcinoma entails excision, generally without systematic therapy. CASE DESCRIPTION: A seventy-year-old woman previously treated definitively for (in situ) breast cancer, undergoes excision of a nodule on the scalp. The histopathology report indicates a lesion typical for cutaneous metastasis of breast carcinoma. However, diagnostic imaging excludes recurrent breast cancer or metastatic spread. When subsequent clonality testing with archived breast cancer tissue from the earlier episode does not show a relation, the pathologist defines the lesion as an eccrine carcinoma. A re-excision is conducted, which does not show any residual tumorous tissue, and at follow-up there are no signs of recurrence or metastases. CONCLUSION: As a relatively rare and unknown malignancy, with strong histopathological resemblance to cutaneous metastasis of breast carcinoma, eccrine carcinoma poses a diagnostic challenge to both clinicians and pathologists.

Are clinicians successful in diagnosing cutaneous adnexal tumors? a retrospective, clinicopathological study

Background/aim: Cutaneous adnexal tumors (CAT) are rare tumors originating from the adnexal epithelial parts of the skin. Due to its clinical and histopathological characteristics comparable with other diseases, clinicians and pathologists experience difficulties in its diagnosis.We aimed to reveal the clinical and histopathological characteristics of the retrospectively screened cases and to compare the prediagnoses and histopathological diagnoses of clinicians. Materials and methods: The data of the last 5 years were scanned and patients with histopathological diagnosis of CAT were included in the study. Results: A total of 65 patients, including 39 female and 26 male patients aged between 8 and 88, were included in the study. The female to male ratio was 1.5, and the mean age of the patients was 46.15 ± 21.8 years. The benign tumor rate was 95.4%, whereas the malignant tumor rate was 4.6%. 38.5% of the tumors were presenting sebaceous, 35.4% of them were presenting follicular, and 18.5% of them were presenting eccrine differentiation. It was most commonly seen in the head-neck region with a rate of 66.1%. When clinical and histopathological prediagnoses were compared, prediagnoses and histopathological diagnoses were compatible in 45% of the cases. Most frequently, it was the basal cell carcinoma, epidermal cyst, and sebaceous hyperplasia identified in preliminary diagnoses. Conclusion: Cutaneous adnexal tumors are very important, as they can accompany different syndromes and may be malignant. Due to difficulties in its clinical diagnosis, histopathological examination must be performed from suspicious lesions for definitive diagnosis.