Microcystic Adnexal Carcinoma Research Articles

A Systematic Review of the Epidemiology, Clinical Characteristics, Treatment, and Outcomes for Desmoplastic Trichoepithelioma: Underscoring Mohs Micrographic Surgery in Management.

Desmoplastic trichoepithelioma (DTE) is an uncommon benign adnexal tumor that histologically may mimic malignant tumors including basal cell carcinoma and microcystic adnexal carcinoma. To present a systematic review of the epidemiology, clinical characteristics, treatment, and outcome data on DTEs, with emphasis on comparing Mohs micrographic surgery (MMS) with other treatments. Using the OVID platform, MEDLINE and Embase were searched from inception for studies providing original data on DTEs. A total of 338 cases of DTE from 61 articles were included. No recurrence/persistence (0%) was reported following MMS (n = 24, mean follow-up of 41.9 months), 13.1% with standard excision (n = 38, mean follow-up 16.9 months), and 2.1% for electrosurgery/cautery (n = 49, follow-up 3-72 months). 100% recurrence/persistence for imiquimod (n = 2) and liquid nitrogen (n = 4) were identified. In patients who underwent biopsy only, there was a 12.5% recurrence/persistence (n = 32, mean follow-up 16.5 months). Overall, duration of follow-up varied from 2 months to 6 years for the various management strategies. Data are limited regarding DTE outcomes. In this review, surgical modalities, specifically MMS, had the lowest rates of recurrence/persistence compared with other options. Given that most lesions are found on cosmetically sensitive locations, MMS seems to be the optimal management strategy for actively managing DTEs.

Perineural Infiltration: A Comprehensive Review of Diagnostic, Prognostic, and Therapeutic Implications.

Perineural infiltration refers to a neoplastic cell involvement in, around, and through the nerves. It is considered as one of the neoplastic dissemination pathways. Thus, its identification is crucial to establish the prognosis of some malignant skin neoplasms, such as squamous cell carcinoma, and explains the locally aggressive behavior of cutaneous neoplasms, such as microcystic adnexal carcinoma. We have conducted a review of malignant and benign skin tumors in which perineural infiltration has been described, and we also discuss some histopathological findings that may simulate perineural infiltration.

A sweaty situation: microcystic adnexal carcinoma in the mature cystic teratoma

A sweaty situation: microcystic adnexal carcinoma in the mature cystic teratoma

Successful Management of Multifocal Microcystic Adnexal Carcinoma of the Head and Neck

Successful Management of Multifocal Microcystic Adnexal Carcinoma of the Head and Neck

Radiotherapy (RT) for Cutaneous Adnexal Carcinoma (CAC): 49 Patients Treated at a Single Institution Over 2 Decades

Cutaneous adnexal carcinomas (CACs) are a heterogenous group of rare skin cancers. Management strategies are extrapolated from the treatment of more common skin cancers, and case series describing patients treated with radiotherapy (RT) for CAC are limited to <15 patients. We reviewed our institutional experience to better understand the characteristics and outcomes of patients with CAC treated with RT. Patients diagnosed with CAC and treated RT from 2000-2020 were identified using the following keywords: adnexal, microcystic, apocrine, eccrine, sebaceous, sweat gland, syringoma, mucinous, tubular, porocarcinoma, hidradenocarcinoma, and cylindrocarcinoma. Patient, cancer, and treatment characteristics were assessed by retrospective record review. Time to overall survival (OS), locoregional recurrence (LRR), distant metastasis (DM), and progression free survival (PFS) were evaluated using Kaplan-Meier methods. Forty-nine patients with a median age of 65 years (IQR 53-82) were identified. Most were white (90%) men (59%) harboring tumors on the head and neck (80%). The most common subtypes of CAC were adnexal adenocarcinoma (39%), sebaceous carcinoma (35%) and microcystic adnexal carcinoma (10%). Patients were treated for de novo cancer (n = 35) or after recurrence (n = 14). Among de novo cases, 9 (26%) were treated with definitive RT, 22 (63%) were treated with surgery and adjuvant RT, and 4 (11%) with palliative RT. Per UICC system, de novo stage at time of RT was I in 2 (6%), II in 9 (26%), III in 12 (34%), IVA in 10 (29%), and IVB in 2 (6%). Median OS was 44 months and median follow-up of surviving patients was 41 months (IQR 17-75). De novo patients treated with definitive RT received a median dose of 70 Gy (IQR 60-73 Gy) and experienced 2-year rates of PFS, LRR, and DM of 30%, 55%, and 40%, respectively. All LRR events occurred within the irradiated volume. De novo patients treated with surgery and adjuvant RT received a median dose of 60 Gy (IQR 60-64 Gy) and experienced 2-year rates of PFS, LRR, and DM of 77%, 13%, and 10%, respectively. All LRR events occurred outside the irradiated volume. Among patients treated at recurrence, most (93%) underwent surgery and adjuvant RT. Per UICC system, their stage at time of RT was II in 2 (15.4%), III in 4 (30.8%), and IVA in 7 (53.8%). Recurrent patients treated with surgery and adjuvant RT received a median dose of 60 Gy (IQR 60-66 Gy) and experienced 2-year rates of PFS, LRR, and DM of 30%, 58%, and 29%, respectively. Three of 4 evaluable patients treated with palliative RT exhibited stable disease or tumor response. In the largest single institution analysis to date, RT was primarily used for CAC patients as an adjuvant treatment. LRR was less frequent and less likely to occur within irradiated volume in patients selected for surgery and adjuvant RT than those selected for definitive RT or at time of recurrence.

43660 Neoadjuvant Radiation to Facilitate Surgical Treatment of a Microcystic Adnexal Carcinoma with Perineural Invasion of the Vulvar Region

43660 Neoadjuvant Radiation to Facilitate Surgical Treatment of a Microcystic Adnexal Carcinoma with Perineural Invasion of the Vulvar Region

Evaluating Rates of Positive Margins After Standard Excision of Cutaneous Adnexal Malignancies.

It is recommended to excise adnexal neoplasms with standard local excision or Mohs micrographic surgery (MMS), although many occur on high-risk sites such as the head and neck (H&N) and exhibit subclinical extension. Minimal evidence exists on the efficacy of standard excisions for these tumors. To evaluate the rate of positive surgical margins after standard excision of adnexal tumors. Retrospective cohort study of cutaneous adnexal malignancies from the National Cancer Database diagnosed from 2004 to 2019. The authors identified a total of 4,402 cases treated with standard excision. Tumors on the H&N were approximately twice as likely as those on the trunk and extremities (T&E) to be excised with positive margins (odds ratio 2.146, p < .001), with the highest estimated rate for eccrine adenocarcinoma (12.1%, SE: 2.3%). The subtype with the highest positive margin rate on the T&E was microcystic adnexal carcinoma (8.0%, SE: 2.9). Positive margins were associated with poorer overall survival on multivariable survival analysis (hazard ratio 1.299, p = .015). The authors present subtype- and site-specific positive margin rates for adnexal tumors treated with standard excision, which suggest that tumors on the H&N and some T&E subtypes, should be considered for MMS.

CPC08 Cutaneous squamous cell carcinoma and MYH9-associated elastin aggregation (MALTA) syndrome

Abstract MYH9-associated elastin aggregation (MALTA) syndrome is a rare, inherited, irregular elastin aggregation and sweat duct proliferation syndrome caused by pathogenic variants in MYH9. MALTA syndrome was proposed in 2019, unifying Nicolau Balus and Rombo syndromes as phenotypes arising from pathogenic variants in the same gene, but it has not been associated with cutaneous squamous cell carcinoma (cSCC) [Fewings E, Ziemer M, Hörtnagel K et al. Malta (MYH9 associated elastin aggregation) syndrome: germline variants in MYH9 cause rare sweat duct proliferations and irregular elastin aggregations. J Invest Dermatol 2019; 139:2238–41]. Here, we report the clinical features of a family with a novel MYH9 c.1952A&amp;gt;C p.(Lys651Thr) pathogenic variant, providing evidence that cSCC may be an associated feature of MALTA syndrome. A 57-year-old woman presented with a longstanding skin lesion overlying her left infraorbital ridge, which had been present for 13 years. Lesion biopsy revealed a highly infiltrative tumour within the dermis that was composed of keratocysts with small islands of basaloid cells; immunostaining was positive for CK5/6, CK7, CK19, p63 and BerEP4. These histological features were consistent with a microcystic adnexal carcinoma (MAC)-like ductal proliferation, recognized in MALTA. In addition, she had previously developed one cSCC on her left shoulder and two basal cell carcinomas and had cutaneous milia. Her sister had a history of MAC-like ductal proliferation and cSCC, and her brother had two keratoacanthoma-like cSCCs. The copresentation of MAC-like ductal proliferations and early-onset cSCC in this family prompted targeted genetic testing of MYH9. This identified a heterozygous pathogenic variant in a highly conserved region of MYH9 [c.1952A&amp;gt;C p.(Lys651Thr)] that segregated with the phenotype in all three affected members. MYH9 has previously been identified as an important gene in the pathogenesis of cSCC in a genetic screen in transgenic mice, and our family adds novel clinical data, underscoring its importance in cSCC development (Schramek D, Sendoel A, Segal JP et al. Direct in vivo RNAi screen unveils myosin IIa as a tumor suppressor of squamous cell carcinomas. Science 2014; 343:309–13). Based on the recurrent presentation of early-onset cSCC in three members of this family, we propose the inclusion of cSCC in MALTA syndrome. This has implications for skin cancer surveillance of MYH9 pathogenic variant carriers, and the need to consider MALTA syndrome in patients presenting with multiple early-onset cSCC.

TRPS1 Is Differentially Expressed in a Variety of Malignant and Benign Cutaneous Sweat Gland Neoplasms

Neoplasms of sweat glands and the breast may be morphologically and immunophenotypically similar. A recent study showed that TRPS1 staining is a highly sensitive and specific marker for breast carcinoma. In this study, we analyzed TRPS1 expression in a spectrum of cutaneous sweat gland tumors. We stained five microcystic adnexal carcinomas (MACs), three eccrine adenocarcinomas, two syringoid eccrine carcinomas, four hidradenocarcinomas, six porocarcinomas, one eccrine carcinoma-NOS, 11 hidradenomas, nine poromas, seven cylindromas, three spiradenomas, and 10 syringomas with TRPS1 antibodies. All of the MACs and syringomas were negative. Every cylindroma and two of the three spiradenomas demonstrated intense staining in cells lining the ductular spaces, with negative to relatively weak expression in surrounding cells. Of the 16 remaining malignant entities, 13 were intermediate to high positive, one was low positive, and two were negative. From the 20 hidradenomas and poromas, intermediate to high positivity was revealed in 14 cases, low positivity in three cases, and negative staining in three cases. Our study demonstrates a very high (86%) expression of TRPS1 in malignant and benign adnexal tumors that are mainly composed of islands or nodules with polygonal cells, e.g., hidradenomas. On the other hand, tumors with small ducts or strands of cells, such as MACs, appear to be completely negative. This differential staining among types of sweat gland tumors may represent either differential cells of origin or divergent differentiation and has the potential to be used as a diagnostic tool in the future.

Improved Margin Control of Microcystic Adnexal Carcinoma After Mohs Micrographic Surgery Compared With Wide Local Excision.

Microcystic adnexal carcinoma (MAC) is a locally aggressive and deeply infiltrative cutaneous tumor primarily treated with excision; however, there are limited data comparing outcomes by surgical approach. To compare surgical outcomes of MAC treated with Mohs micrographic surgery (MMS) and wide local excision (WLE). A 27-year retrospective cohort study of primary MAC was performed. Surgical (i.e. margin status after resection) and recurrence outcomes (including local recurrence [LR], nodal metastases [NM], and distance metastases [DM]) were analyzed by type of surgical approach (MMS and WLE). Sixty-nine MACs were included, of which 34 (49.3%) were treated with MMS and 35 (50.7%) with WLE. All MMS-treated tumors had negative margins after the first surgery attempt. Twenty-one (60.0%) tumors treated with WLE had positive margins after the first surgical attempt and required additional procedures. More tumors treated with WLE developed LR, NM, or DM, although this did not meet statistical significance. Retrospective single institution study. Greater than half of MAC tumors treated with WLE had positive margins after the initial surgery and required multiple procedures for complete removal. Real-time complete margin assessment is important for this locally aggressive and infiltrative tumor.

Nodulo-Ulcerative Plaque Over the Vertex of Scalp.

A 45-year-old man presented with a 12-year-old swelling in the vertex region of his scalp that had gradually grown in size for the last few years. Pus discharge and minor pain had been present for the previous 10 days. Patient had received treatment with oral and topical antibiotics. There was no history of preceding trauma, nevoid lesions, or associated comorbidities. Cutaneous examination revealed a hard non-tender fixed plaque of 3 cm × 2 cm size over vertex area of scalp with central ulceration and yellowish white discharge. It was separated from surrounding skin with a sharp demarcation [Figure 1]. There was no regional lymphadenopathy.Figure 1: Single hard, non-tender fixed plaque of 3 cm × 2 cm size over vertex area of scalpSkin biopsy from the lesion revealed an epithelial neoplasm in the dermis reaching up to the base and both lateral margins without any connection with the epidermis [Figure 2]. Upper dermis and mid-dermis showed numerous dilated keratin cysts and orthokeratotic corneocytes [Figure 2]. Mid- and lower dermis showed numerous small rounded and elongated tumor islands made up of basaloid cells without too much atypia with ductal structures or differentiation at their center and surrounded by dense fibroblastic stroma. Some of these ducts were elongated and dilated but were lined by cuboidal basaloid cells without any signs of apocrine differentiation [Figure 3].Figure 2: An epithelial neoplasm in the dermis reaching up to the base and both lateral margins but showing no connection with surface epidermis (H & E 40x)Figure 3: In the mid-dermis and lower dermis, the neoplasm shows numerous keratin cysts, many of which are dilated and show orthokeratotic corneocytes, majority of the tumor islands are small and rounded, while others are small irregular and surrounded by dense fibroblastic stroma, numerous rounded and elongated tumor islands made up of basaloid cells without too much atypia (H&E 100x)What is the diagnosis? Answer Microcystic adnexal carcinoma. Discussion Microcystic adnexal carcinoma (MAC) is a rare, slow-growing but locally aggressive malignant neoplasm with low mortality rate and it rarely metastasizes.[1] It arises from pluripotent keratinocytes and shows characteristic pilar and eccrine differentiation.[1] It was first described in 1982 by Goldstein et al. as a distinct clinicopathologic entity.[2] It is reported mainly in adults between 55 and 60 years of age with a slight female preponderance. Clinically, it presents as a solitary asymptomatic plaque or nodule most commonly on the head and neck areas. Occasionally, patients may present with pain, itching, burning sensation, numbness, and tingling as a result of perineural invasion by the tumor.[2] Immunosuppression, UV radiation exposure, and radiotherapy are the predisposing factors.[2] MAC is commonly misdiagnosed as desmoplastic trichoepithelioma (DT), syringoma, morpheaform basal cell carcinoma (mbcc), and desmoplastic squamous cell carcinoma (SCC) on histopathology.[3] It is often difficult to clinically distinguish MAC from other skin-colored growths on the head and neck including BCC. Histopathologically, the presence of ductal structures helps to differentiate MAC from DT, whereas the presence of calcification, prominent horn cysts, and single-file strand formation differentiates MAC from syringoma. Among all these tumors, perineural and subcutaneous involvement is characteristic feature of MAC on histopathology. MAC is also characterized by presence of normal tissue between epidermis and dermis.[4] Immunohistochemical markers that help to distinguish MAC from morpheaform BCC and SCC include cytokeratin 15 (CK15), carcinoembryonic antigen (CEA), and BerEP4 [Table 1].[5]Table 1: Immunohistochemical markers to distinguish MAC from morpheaform BCC and SCCThe most definitive treatment for MAC is complete surgical excision. Mohs micrographic surgery (MMS) is the preferred option as it is associated with low recurrence rate.[6] MAC has a high recurrence rate that ranges from 15% to 60% depending on the treatment option used. Recurrence may occur many years following the excision; hence, long-term follow-up is mandatory. Other treatment options include wide local excision, adjuvant or definitive radiotherapy, and chemotherapy.[7] Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

MICROCYSTIC ADNEXAL CARCINOMA OF THE SCALP WITH NODAL METASTASIS TREATED WITH SURGERY AND RADIOTHERAPY: CASE REPORT

Microcystic adnexal carcinoma is an uncommon type of cutaneous neoplasm known by its slow growth but local aggressivity and no potential of systemic metastasis. The standard diagnostic approach is histopathological study of a deep incisional or excisional biopsy. The literature has detailed a variety of treatment modalities, including the Mohs micrographic surgery, standard excision, radiation therapy, chemotherapy, or observation.Mohs is nonetheless the recommended approach nowadays. We describe a unique case of a 69-year-old woman presenting reccurrent Microcystic adnexal carcinoma of the scalp with histologically proven spinal lymph node involvement, treated with surgery, lymph node dissection, and adjuvant radiotherapy. the ongoing assessment shows no evidence of clinical or radiological recurrence at 28 months post-treatment.

Margin Size for Unique Skin Tumors Treated With Mohs Micrographic Surgery: A Survey of Practice Patterns.

Mohs micrographic surgery (MMS) has shown lower recurrence rates for unique skin tumors compared with wide local excision, but there is a lack of standardization on margin size. We aimed to assess MMS practice patterns of margin sizes for unique skin tumors. A survey was distributed to members of the American College of Mohs Surgery (ACMS). Demographic information on participants was collected in addition to initial/subsequent MMS margin size for unique skin tumors, including dermatofibrosarcoma protuberans (DFSP), atypical fibroxanthoma (AFX), melanoma, sebaceous carcinoma, microcystic adnexal carcinoma (MAC), poorly differentiated squamous cell carcinoma (SCC), and Merkel cell carcinoma. Eighty-seven respondents completed the survey (response rate <10%). Given that no guidelines exist on MMS margins for less commonly treated skin tumors, this study helps give Mohs surgeons perspective on current practice patterns for margin sizes. Mohs surgeons are more likely to take larger initial margins for these common skin tumors compared with BCCs or SCCs.

Four calcium signaling pathway-related genes were upregulated in microcystic adnexal carcinoma: transcriptome analysis and immunohistochemical validation

BackgroundMicrocystic adnexal carcinoma (MAC) is a skin cancer with challenges in diagnosis and management. This study was aimed to detect molecular alterations of MAC and guide its pathologic diagnosis and treatment.MethodsWe performed transcriptome analysis on 5 MAC and 5 normal skin tissues, identified the differentially expressed genes, and verified them by immunohistochemistry.ResultsThree hundred four differentially expressed genes (DEGs) in MAC were identified by next-generation transcriptome sequencing, among which 225 genes were upregulated and 79 genes were downregulated. Four genes of the calcium signaling pathway, including calcium voltage-gated channel subunit alpha 1 S (CACNA1S), ATPase sarcoplasmic/endoplasmic reticulum Ca2+ transporting 1 (ATP2A1), ryanodine receptor 1 (RYR1), and myosin light chain kinase 3 (MYLK3), were upregulated and then been verified by immunohistochemistry. The expression of CACNA1S, ATP2A1, RYR1, and MYLK3 was upregulated in MAC compared with normal sweat glands and syringoma tumor cells and was generally negative in trichoepithelioma and infundibulocystic type basal cell carcinoma.ConclusionsThe four genes of the calcium signaling pathway were upregulated in MAC at both RNA and protein levels. CACNA1S, ATP2A1, RYR1, and MYLK3 may be new diagnostic molecular markers and therapeutic targets for MAC.

Head and Neck Sweat Gland Carcinomas: Clinical Characteristics and Patterns of Care

<h3>Purpose/Objective(s)</h3> Little is known about head and neck malignancies originating from cutaneous adnexal tissue. Using the National Cancer Database (NCDB), we attempted to characterize patients with malignant sweat gland carcinomas of the head and neck region. <h3>Materials/Methods</h3> Adult patients with malignant head and neck sweat gland carcinomas diagnosed between 2004-2018 in the NCDB were selected. Demographics, comorbidities, tumor characteristics, and treatments were analyzed. Patients with unknown survival outcomes, no surgical treatment, less than six months of follow-up, previous malignancies, or T0 tumors were excluded from survival analysis. Kaplan-Meier analysis was used to assess overall survival at three and five years. Cox proportional-hazards regression was used to assess for predictors of overall survival. <h3>Results</h3> We identified 2723 patients with sweat gland carcinomas in the NCDB. The median age was 68 years (range: 20-90), and 1366 patients (50.2%) were female. The most common histology was microcystic adnexal carcinoma (676, 24.8%) followed by mucinous carcinoma (535, 19.6%) and porocarcinoma (419, 15.4%). Of patients with complete staging information, most were staged as T1 (916, 63.0%), N0 (1871, 97.2%), and M0 (2278, 99.3%). Nodal metastases were present in 94 patients (10.1%). The highest rates of nodal disease were observed in apocrine adenocarcinoma (29.0%), squamoid eccrine ductal carcinoma (17.5%), and porocarcinoma (16.6%). Excluding these histologies, the nodal metastasis rate was 6.5%. 2559 patients (95.4%) were treated with surgery. Of these, 334 (12.9%) received adjuvant radiation and 29 (1.1%) received chemoradiation. Three-year and five-year overall survival rates were 88.1% (95% CI: 86.5%-89.6%) and 80.3% (78.3%-82.4%), respectively. On univariable analysis, age, male gender, white race, comorbidities, treatment at a community hospital, tumor size >1cm, T and N stage, lymphovascular invasion, and positive margins were associated with worse survival. Age, male gender, comorbidities, size >1cm, and nodal stage retained their significance in multivariable analysis. <h3>Conclusion</h3> Sweat gland carcinomas are a diverse group of rare malignancies. While the rate of nodal metastases is low, certain histologies harbor higher potential for lymph node metastases with worse survival. Tumor size larger than 1cm is also associated with worse survival. The above data could help clinicians in the management of these rare tumors.

A review of Mohs micrographic surgery for skin cancer. Part 1: Melanoma and rare skin cancers.

Mohs micrographic surgery (MMS) is a precise and effective method commonly used to treat high-risk basal cell carcinoma and squamous cell carcinoma on the head and neck. Although the majority of evidence for MMS relates to keratinocyte cancers, there is published evidence for other types of skin cancer. This review aims to discuss the evidence for using MMS to treat six different types of skin cancer [malignant melanoma, lentigo maligna, dermatofibrosarcoma protuberans, atypical fibroxanthoma (AFX), microcystic adnexal carcinoma and pleomorphic dermal sarcoma (PDS)] particularly in the context of survival rates and cancer recurrence. These cancers were chosen because there was sufficient literature for inclusion and because MMS is most useful when cancers are contiguous, rather than for cancers with marked metastatic potential such as angiosarcoma or Merkel cell carcinoma. We searched MEDLINE, PubMed and Embase using the keywords: 'melanoma', 'mohs micrographic surgery', 'lentigo maligna', 'dermatofibrosarcoma protuberans', 'atypical fibroxanthoma', 'microcystic adnexal carcinoma' and 'pleomorphic dermal sarcoma' along with their appropriate synonyms, to identify the relevant English-language articles from 2000 onwards, given that literature for MMS on nonkeratinocyte cancers is sparse prior to this year. AMSTAR (A MeaSurement Tool to Assess systematic Review) was used to assess the validity of systematic reviews. Further high-quality, multicentre randomized trials are necessary to establish the indications and efficacy of MMS for rarer cancers, particularly for AFX and PDS, for which only limited studies were identified.

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

PurposeTo prospectively assess the impact of expert pathological review of skin adnexal carcinoma diagnosis in France. MethodsFrom 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. ResultsThe 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). ConclusionThe 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.

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

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. 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. 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. 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.

Sclerosing Microcystic Adenocarcinoma: A Case Report and Review of Literature

Abstract Sclerosing microcystic adenocarcinoma is an extremely rare tumor that was described by Mills et al in 2016 and occurs in the head and neck region. There are 8 cases published with this terminology in the English language literature. Here, we present a 59-year-old female patient with sclerosing microcystic adenocarcinoma in the anterolateral tongue and review the previously reported 8 cases. Most of the reported cases are in females and localized to the tongue. This tumor mimics microcystic adnexal carcinoma, which is a cutaneous-based malignant tumor. The tumor in the present case was composed of cells that were arranged in nests or gland-like structures, with had ductular differentiation in a densely sclerotic stroma. The diagnosis of sclerosing microcystic adenocarcinoma may be difficult because of its paucicellular histomorphology. Surgical margins can be problematic to assess. Several salivary gland tumors should be included in the differential diagnosis, such as adenoid cystic carcinoma, polymorphic adenocarcinoma, and mucoepidermoid carcinoma. The role of immunohistochemistry in this differential diagnosis is limited. Therefore, the diagnosis depends on routine histology.

Microcystic adnexal carcinoma of the scalp treated with surgical resection along with chemoradiation: A case report and review of the literature.

Microcystic adnexal carcinoma (MAC) is an infiltrative rare cutaneous neoplasm for which there are no consensus management guidelines because of the paucity of evidence-based practice; hence, the utility of their management is based only on previously published case reports. We report a case of a scalp lesion that was successfully treated using a combination of surgical resection, chemotherapy, and radiotherapy.