The burden of cutaneous adnexal carcinomas and the risk of associated squamous cell carcinoma: a population-based study.

BACKGROUND: Recent studies have shown an increasing incidence of cutaneous adnexal carcinomas (CACs). OBJECTIVES: The aim of our study was to evaluate incidence and survival for cases of CACs and investigate their association with other skin neoplasms. METHODS: We conducted a population-based study. Data on incident cases of CACs were obtained from the Tuscany Cancer Registry between 1985 and 2010. In order to determine whether the occurrence of squamous cell carcinoma (SCC) among patients with CAC is higher or lower than expected in the general population, the standardized incidence ratio (SIR) was calculated. RESULTS: A total of 242 patients with CAC were observed; the age-standardized incidence rate was 3·8 cases per million person-years. From 1997 to 2010 crude incidence rates increased by 159%. Age-specific incidence was higher in men over 80 years old than in women of the same age and younger individuals. Carcinomas of sweat gland origin prevailed; the most common histotype was porocarcinoma and the most frequently affected site was the head/neck. Overall, 88% of CACs were diagnosed at a localized stage. The 5-year overall survival and disease-specific survival rates were 59% [95% confidence interval (CI) 53-65] and 94% (95% CI 91-98), respectively. In the observation cohort, the number of SCCs was significantly higher than expected as the SIR was calculated to be 33·7 (P < 0·001). CONCLUSIONS: Increasing incidence warrants awareness and early diagnosis of CACs. Increased SCC incidence among patients with these tumours highlights the relevance of careful skin examination and follow-up.

Increasing incidence and survival of a rare skin cancer in the Netherlands. A population-based study of 2,220 cases of skin adnexal carcinoma.

BACKGROUNDS AND OBJECTIVES: The aim of this study was to describe the epidemiology and treatment of skin adnexal carcinoma (SAC) in the Netherlands and to identify prognostic factors for survival in patients with SAC. METHODS: We used population-based nationwide data from the Netherlands Cancer Registry with cases diagnosed during 1989-2010 and followed up to February 1st, 2012. RESULTS: A total of 2,220 SACs were diagnosed during 1989-2010 (age-standardized incidence rate 5.3 per million). Incidence increased by 2.7% and 1.7% annually in males and females, respectively. Fifteen different morphological types were registered. The 5-year relative survival rate increased from 80% in 1989-1994 to 91% in 2006-2010. The majority of all patients (91%) received surgery. Adjuvant radiotherapy and/or lymph node dissection was performed in only a minority of cases. The risk of death was significantly higher in patients who did not receive surgery. CONCLUSIONS: The rising incidence of SAC together with the predilection for the head and neck region suggests a role for UV radiation in the carcinogenesis of SAC. Furthermore, we found an improved survival of SAC in the Netherlands between 1989 and 2010. In view of the low proportion of patients receiving adjuvant therapy there may be further room for improving survival.

Genetic skin diseases predisposing to basal cell carcinoma.

Basal cell carcinoma (BCC) is the commonest cancer in humans. Predisposing factors reflect common genetic variations and environmental influences in most cases. However, an underlying Mendelian disorder should be suspected in a specific subset of patients, namely those with multiple, early onset lesions. Some specific conditions, including Gorlin, Bazex-Dupré-Christol and Rombo syndromes, and Xeroderma Pigmentosum, show BCC as a prominent feature. In addition, BCC may represent a relatively common, although less specific, finding in many other genodermatoses. These include disorders of DNA replication/repair functions (Bloom, Werner, Rothmund-Thomson and Muir-Torre syndromes), genodermatoses affecting the folliculo-sebaceus unit (Brooke-Spiegler, Schöpf-Schulz-Passarge and Cowden syndromes), immune response (cartilage-hair hypoplasia and epidermodysplasia verruciformis) and melanin biosynthesis (oculocutaneous albinism and Hermansky-Pudlak syndrome), and some epidermal nevus syndromes. Further conditions occasionally associated with BCCs exist, but the significance of the association remains to be proven.

Adnexal skin tumors in Zaria, Nigeria.

BACKGROUND: Adnexal skin tumors share many features in common and differentiate along one line. Their detailed morphological classification is difficult because of the variety of tissue elements and patterns seen. They may be clinically confused with other cutaneous tumors. The aim of this report is to review and classify all adnexal tumors seen in a pathology department over a 16-year period. METHOD: A 16-year retrospective analysis of all adnexal skin tumors seen in a large University Teaching Hospital in Nigeria from January 1991- December 2006. All tissue specimens were fixed in 10% formalin, processed in paraffin wax and stained with Haematoxylin and Eosin. Histology slides were retrieved, studied and lesions characterized. RESULTS: Fifty-two adnexal tumors were seen, accounting for 0.9% of all cutaneous tumors seen within the same period. The median age was 33 years (range: 4 days-70 years). Clinical presentations varied from discreet swellings and nodules to ulcerated masses. Five patients presented with recurrent lesions. Only two cases had a clinical diagnosis of adnexal tumor. Twenty-four (46%) of the lesions were distributed in the head and neck region. Duration of symptoms was 2 months to 15 years (median: 12 months). Tumours of the sweat gland were the commonest--41 (78.8%); they comprised predominantly eccrine acrospiroma (17), characterized histologically by solid nests of round to polygonal cells with clear to eosinophilic cytoplasm, forming tubules in areas. Tumours of sebaceous gland were 7 (13.5%); they comprised mainly Nevus sebaceous of Jadassohn (6), composed of immature sebaceous glands and pilar structures microscopically and a solitary sebaceous adenoma. Tumours of hair follicle were 4 (7.7%) and included trichoepithelioma, characterized microscopically by multiple horn cysts and epithelial tracts connecting abortive pilar structures and a trichofolliculoma. Forty-six lesions (88.5%) were benign and six (11.5%) malignant. CONCLUSION: Adnexal skin tumors have distinct histological patterns which differentiates them from other cutaneous tumors. They are commonly distributed in the head, neck and trunk. The commonest variants are those of eccrine sweat gland origin. Malignant adnexal tumors are uncommon in our setting.

[Malignant cutaneous adnexal neoplasms of the face and scalp: Diagnostic and therapeutic update]. / Les tumeurs cutanées malignes à différentiation pilaire de la face et du cuir chevelu : mise au point diagnostique et thérapeutique.

INTRODUCTION: Malignant cutaneous adnexal neoplasms are rare and have been characterized only recently. They can occur at any age but preferentially in elderly. There are 3 of them: trichoblastic carcinoma, trichilemmal carcinoma and malignant pilomatricoma. The aim of our study was to make a diagnostic and therapeutic update about these tumors when located at the face or at the scalp. MATERIALS AND METHODS: A bibliographic research was made on PubMed using following keywords: appendage skin carcinoma AND pathology AND/OR therapeutic. Articles published before 2000 were considered outdated and were excluded. RESULTS: Twenty-five articles met the inclusion criteria. Clinical presentation was non-specific. Histological examination only allowed for diagnosis. Lesions were locally or loco-regionally aggressive. Lymphatic or hematogenous metastasis were reported. No consensus about treatment was found. When surgery was used, it consisted in resection with safety margins ranging from 0.5 to 3cm depending on the teams. In case of metastasis, treatment consisted in chemo- and/or radiotherapy. A quarterly medical monitoring was recommended. DISCUSSION: Malignant cutaneous adnexal tumors are rare. There is nowadays no treatment consensus. An initial staging by mean of a head and neck, chest, abdominal and pelvic CT-scan is mandatory. Treatment has to be decided in a multidisciplinary cancer committee. In the absence of metastasis, the reference treatment is surgical resection, possibly by Mohs micrographic technique, with large safety margins. In case of metastasis or if the loco-regional extension does not allow for a complete excision, chemotherapy and/or radiotherapy may be proposed. A close monitoring is essential.

Microcystic adnexal carcinoma: treatment with Mohs micrographic surgery.

BACKGROUND: Microcystic adnexal carcinoma (MAC) is reported to have a high rate of recurrence with standard wide local excision. OBJECTIVE: To report a large series of patients with MAC treated with Mohs micrographic surgery (MMS). METHODS: This prospective, multi-center case series included all patients in Australia treated with MMS for MAC, who were monitored by the Skin and Cancer Foundation between 1993 and 2002. RESULTS: There were 44 cases; most of them (90.9%) were located in the head and neck area. In 31.8% of cases it was a recurrent tumor. In 32.5% of cases the tumor was initially misdiagnosed as basal cell carcinoma or squamous cell carcinoma. Perineural invasion was recorded in 17.5% of cases; most of them (85.7%) were previously recurrent tumors. There was only one case of recurrence (5%) out of 20 patients who completed a 5 year follow-up period after MMS. CONCLUSION: The low 5-year recurrence rate of MAC with MMS emphasizes the importance of margin-controlled excision.

Benign ocular adnexal tumours of apocrine, eccrine or hair follicle origin.

BACKGROUND: The differential diagnosis of malignant eyelid tumours, particularly basal cell carcinoma (BCC), includes tumours of skin appendages. The incidence of these adnexal tumours has not been well established. This study aimed to determine the incidence and review the main clinicopathological features of benign tumours arising from skin appendages of the eyelid with apocrine, eccrine or hair follicle differentiation. METHODS: The histopathological diagnoses of 7751 ophthalmic specimens retrieved from 6967 patients between September 1993 and March 2002 at the Henry C. Witelson Ophthalmic Pathology Laboratory and Registry, McGill University, Montreal, were retrospectively reviewed. Clinical data and histopathological diagnoses were obtained for 228 benign adnexal tumours of apocrine, eccrine or hair follicle origin. New histopathological slides were made from the paraffin-embedded specimens and stained with hematoxylin-eosin and periodic acid-Schiffs reagent. RESULTS: Of the 228 benign adnexal tumours, 182 were diagnosed as apocrine or eccrine hydrocystoma (79.8%), 12 pilomatrixoma (5.3%), 12 syringoma (5.3%), 11 trichilemmoma (4.8%), 5 syringocystadenoma papilliferum (2.2%), 3 trichoepithelioma (1.3%) and 3 trichofolliculoma (1.3%). Discrepancies between clinical and histopathological diagnoses were noted in 22 cases (9.6%). INTERPRETATION: Benign tumours originating from skin appendages of the eyelid are rare and frequently have apocrine or eccrine differentiation. These tumours, particularly those originating from the hair follicle, should be considered in the differential diagnosis of BCC of the eyelid.

Cutaneous adnexal neoplasms in biopsy specimens processed in the Department of Pathology, University of Malaya.

A review of consecutive biopsies of adnexal tumours from 112 patients, received by the Department of Pathology, University of Malaya, over a 13-year period was undertaken. The age range of the patients was from 1 to 84 years, with a mean of 29.8 years. Thirty-three (32%) patients were under 20 years of age. There were 68 females with a male to female ratio of 1.0:1.5. In 105 cases (93.7%), the neoplasm was solitary. The tumour measured less than 2 cm in the largest dimension in 103 cases (92%). The common sites of occurrence were the head and neck region (59%) and extremities (25%). Neoplasms of hair follicle origin accounted for 63.4% (71 cases) of all lesions. Intra-tumour deposition of amyloid was noted in one of the 14 cases of trichoepithelioma.

Spectrum of cutaneous appendage tumors at Aga Khan University Hospital.

OBJECTIVE: To determine the frequency of various types of cutaneous appendage tumors in our practice. METHOD: This is a partly retrospective and partly prospective study conducted at the Department of Pathology, Histopathology Section, The Aga Khan University Hospital, Karachi between 1st January 1997 and 31st December 2001. RESULTS: One hundred sixty six skin appendage tumors were diagnosed during the study period. 87.3% were benign, while 12.6% were malignant. Male female ratio was almost equal. Mean age was 41.72 years. 37.34% showed eccrine differentiation, 14.45% showed apocrine differentiation and 41.56% showed pilosebaceous differentiation, 6.62% exhibited mixed differentiation. The 5 commonest tumors were pilomatricoma, nodular hidradenoma (eccrine acrospiroma), syringocystadenoma papilleferum, eccrine poroma and eccrine spiradenoma. The commonest malignant tumors were porocarcinoma and sebaceous carcinoma. Pilomatricoma were common in children. CONCLUSION: Most of our findings roughly correlate with the western published data. However, commonest site for eccrine poromas in our study was head and neck. Also, not a single case of eccrine spiradenoma was seen in the first two decades of life. These findings differ significantly from western data.

[Adnexal neoplasms in the context of skin cancer: trichilemmal carcinoma. Apropos of a case]. / Neoplasias de anexos en el contexto del cáncer de piel: el carcinoma triquilemal. A propósito de un caso.

BACKGROUND: The trichilemmal carcinoma is a rare malignant neoplasm, whose origin lies in the annexes of the skin, because of its low prevalence often confused with other dermal tumors, the differential diagnosis is not easy and is usually made by exclusion; in theory, its behavior is slow with little tendency to send both regional lymph node metastasis and systemic. Due to the limited number of cases there is no consensus on the prognosis, although it is generally considered good. The aim of this report is to show a case that, contrary to previous reports, the clinical presentation is aggressive with large soft tissue tumor infiltration around the site of origin in a patient without risk factors for skin cancer. CLINICAL CASE: Male patient, 65 years old with cytologic diagnosis of carcinoma in a preprarotideal facial tumor, characteristics at diagnosis were infiltration of the facial skin, ear, and parotid gland. Complete block resection was performed, radical parotiroidectomy and radical neck dissection; the soft tissue defect was covered with a pediculated flap. The evolution was satisfactory it follow-up short though. We evaluated the experience in the literature regarding the prognosis and treatment of these patients. CONCLUSION: Trichilemmal carcinoma can be fully invasive behavior prognosis is difficult to know and probably depends on the clinical stage at diagnosis.

Antecedente: el carcinoma triquilemal es una neoplasia maligna poco frecuente originada en los anexos de la piel. Debido a su escasa prevalencia suele confundirse con otros tumores dérmicos, su presentación clínica no favorece el diagnóstico diferencial y generalmente éste se hace por exclusión. En teoría, su comportamiento es lento, con poca tendencia a enviar metástasis regionales ganglionares y sistémicas. Debido al escaso número de casos no existe consenso en relación con el pronóstico, aunque generalmente se estima bueno. El objetivo de este reporte es mostrar un caso que, contrario a lo informado, es de manifestación agresiva en un paciente sin factores de riesgo para cáncer de piel, con gran infiltración tumoral de los tejidos blandos alrededor del sitio de origen. Caso clínico: paciente masculino de 65 años de edad que acudió con diagnóstico citológico de carcinoma en un tumor facial preparotídeo; al momento del diagnóstico motraba infiltración de la piel de la cara, del pabellón auricular y de la glándula parótida. Se efectuó resección completa de la neoplasia en bloque con isla de piel facial, parotidectomía total y disección radical del cuello; el defecto de partes blandas fue cubierto con un colgajo pediculado. La evolución ha sido satisfactoria; sin embargo, el seguimiento es corto. Se evalúa la experiencia asentada en la bibliografía en relación con el pronóstico y tratamiento de estos pacientes. Conclusión: el carcinoma triquilemal puede tener comportamiento localmente invasor lo que hace difícil determinar el pronóstico, que quizá dependa de la etapa clínica al momento del diagnóstico.

Nonmelanoma skin cancer.

Nonmelanoma skin cancer (NMSC) is the most common form of malignancy in humans. The incidence of NMSC continues to increase despite increased awareness and sun-protective measures. If neglected or mismanaged, NMSC can cause significant morbidity and even death. The most common forms of NMSC on the head and neck include basal cell carcinoma, squamous cell carcinoma, sebaceous carcinoma, eccrine porocarcinoma, Merkel cell carcinoma, atypical fibroxanthoma, and microcystic adnexal carcinoma. Surgery is the mainstay of treatment (standard excision, Mohs micrographic surgery, curettage); however, other modalities exist, including radiation, topical immunomodulators, photodynamic therapy, and new systemic medications.

Descriptive epidemiology of malignant mucosal and uveal melanomas and adnexal skin carcinomas in Europe.

This work provides descriptive epidemiological data of malignant mucosal and uveal melanomas and adnexal skin carcinomas in Europe as defined as in the RARECARE project. We analysed 8669 incident cases registered in the period 1995-2002 by 76 population-based cancer registries (CRs), and followed up for vital status to 31st December 2003. Age-standardised incidence to the European standard population was obtained restricting the analysis to 8416 cancer cases collected by 64 not specialised CRs or with information available only for some anatomical sites. Period survival rates at 2000-2002 were estimated on 45 CRs data. Twenty-two CRs which covered the period 1988-2002 were analysed to obtain the 15-year prevalence (1st January 2003 as reference date). Complete prevalence was calculated by using the completeness index method which estimates surviving cases diagnosed prior to 1988 ('unobserved' prevalence). The expected number of new cases per year and of prevalent cases in Europe was then obtained multiplying the crude incidence and complete prevalence rates to the European population at 2008. We estimated 5204 new cases per year (10.5 per million) to occur in Europe, of which 48.7% were melanomas of uvea, 24.8% melanomas of mucosa and 26.5% adnexal carcinomas of the skin. Five-year relative survival was 40.6% and 68.9% for mucosal and uveal melanomas, respectively. Adnexal skin carcinomas showed a good prognosis with a survival of 87.7% 5 years after diagnosis. Northern Europe, United Kingdom (UK) and Ireland showed the highest 5-year survival rate for uveal melanomas (72.6% and 73.4%), while Southern Europe showed the lowest rate (63.7%). More than 50,000 persons with a past diagnosis of one of these rare cancers were estimated to be alive at 2008 in Europe, most of them (58.8%, n=29,676) being patients with uveal melanoma. Due to the good prognosis and high incidence of uveal melanomas, these malignancies are highly represented among the long-term survivors of the studied rare cancer types. Therefore, maximising quality of life is particularly important in treatment of uveal melanoma. As regards mucosal melanomas, the centralisation of treatment to a select number of specialist centres as well as the establishment of expert pathology panels should be promoted. The geographical differences in incidence and survival should be further investigated analysing the centre of treatment, the stage at diagnosis and the treatment.

Uncommon cutaneous neoplasms of the head and neck.

This article concentrates on the less-common cutaneous malignancies such as merkel cell, atypical fibroxanthoma, malignant fibrous histiocytoma, dermatofibrosarcoma protuberans, microcystic adnexal carcinoma, and sebaceous carcinoma. The clinical and histopathologic descriptions of each, most current and emerging etiologies, diagnosis, staging, treatment, and prognosis are discussed.

Surveillance, Epidemiology, and End Results (SEER) database analysis of microcystic adnexal carcinoma (sclerosing sweat duct carcinoma) of the skin.

BACKGROUND: Microcystic adnexal carcinoma (MAC) is a very rare cancer of the skin. It has only been described previously in case reports and small retrospective series. OBJECTIVE: To analyze and summarize data from the National Cancer Institute, Surveillance, Epidemiology, and End Results (SEER) database regarding MAC. METHODS: The SEER 1973 to 2004 database was investigated, and patients with MAC were identified. A statistical analysis was performed. RESULTS: Two hundred twenty-three patients were identified. Predominant site of disease was the head and neck skin (74%). There was only 1 case of recorded metastatic disease. Lymph nodes were pathologically involved in 1%. The 10-year overall survival was 86.4% (Standard Error [SE]: 3.3%). US census population-matched relative survival was 97.7% at 10 years (SE: 5.2%). LIMITATIONS: This study is limited by the retrospective nature of the SEER database. CONCLUSIONS: MAC is locally invasive, and rarely metastasizes to lymph nodes. Overall and population-matched relative survival is excellent.

Cutaneous appendageal carcinoma incidence and survival patterns in the United States: a population-based study.

OBJECTIVE: To examine incidence patterns of patients diagnosed as having cutaneous appendageal carcinoma (CAC). DESIGN: Population-based study using the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute data from 1978 through 2005. PARTICIPANTS: A total of 1801 subjects from SEER 16 registries (2001-2005) for incidence analyses, 2228 from SEER 9 registries (1987-2005) for trend analysis, and 1984 subjects (1992-2004) for survival analysis. MAIN OUTCOME MEASURE: Incidence rates (IRs) per 1 million person-years according to anatomic site, race, sex, age, and histologic type. RESULTS: Cutaneous appendageal carcinomas are uncommon (age-adjusted IR, 5.1 per 1 million person-years), with the IR among men statistically significantly higher than women (6.3 vs 4.2, respectively; male to female IR ratio 1.51; P < .001). Hispanic whites (IR, 3.7), blacks (IR, 3.5), and Asian/Pacific Islanders (IR, 2.5) all had significantly lower IRs than non-Hispanic whites (IR, 5.7) (P < .001). Apocrine-eccrine carcinoma overall was the most common category (IR, 2.6), and the IR was highest among non-Hispanic white (IR, 2.8) compared with other ethnic/racial groups (P < .001). Cutaneous appendageal carcinomas IRs rose 100-fold with age, from 0.37 among those aged 20 to 29 years to 37.3 among those 80 years or older. From 1978-1982 to 2002-2005, the CAC IRs increased 150%, from 2.0 to 5.0; the apocrine-eccrine carcinoma and the sebaceous carcinoma IRs rose 170%, from 1.0 to 2.7, and 217%, from 0.6 to 1.9, respectively. Five-year relative survival rates overall were 99% for localized and 43% for distant disease. CONCLUSIONS: Cutaneous appendageal carcinomas are rare tumors with IRs that vary by sex and racial/ethnic group. Cutaneous appendageal carcinoma IRs are increasing in the United States, especially for sebaceous carcinoma, perhaps related to improved recognition and classification, but factors such as UV exposure and immunosuppression may also play a role.

Microcystic adnexal carcinoma: an uncommon tumor with debatable origin.

BACKGROUND: Microcystic adnexal carcinoma is an uncommon skin appendage neoplasm exhibiting both pilar and sweat duct differentiation. This tumor remains a subject of controversy as to its differentiation profile, histogenesis, and classification which is reflected in the nomenclature used to designate the neoplasm in question. Beyond this controversy the tumor remains a diagnostic challenge because of its rarity, the histologic mimicry it may display, and its banal cytologic appearance; it also poses a therapeutic challenge, as it is characterized by slow but aggressive and destructive local growth extending beyond clinical margins together with a high tendency for perineural invasion and recurrence. OBJECTIVE: We report two cases of this unusual tumor illustrating some of its characteristics. Our review emphasizes the divergent opinions concerning its differentiation profile and its origin. An organoid nevus as the origin of microcystic adnexal carcinoma in one of our patients is discussed in this context.

Microcystic adnexal carcinoma: review of 51 Japanese patients.

BACKGROUND: Microcystic adnexal carcinoma (MAC) has been reported to occur predominantly in Caucasians. However, the number of cases in Japanese subjects seems to have recently been increasing. OBJECTIVE: To review the Japanese cases of MAC. METHODS: We collected and analyzed the data of 51 Japanese patients recorded in case reports or abstracts over a number of years. RESULTS: Twenty-five of the cases were reported between 1987 and 1996, and the remaining 26 cases between 1997 and 2000. Forty-three lesions were located on the face, 2 on the scalp, 2 on the chest, 1 on the axilla, 1 on the buttock, 1 on the palm and 1 on the toe. One of the above occurred at the site of previous radiotherapy. Fifteen tumors were initially misdiagnosed histopathologically. CONCLUSION: Our review shows that MAC also occurs in the Japanese, in whom it may be more common than previously observed.

High frequency and diversity of cutaneous appendageal tumors in organ transplant recipients.

BACKGROUND: Recipients of organ transplant who are immunosuppressed are at greatly increased risk of nonmelanoma skin cancers compared with the general population, but their risk of appendageal tumors is unknown. OBJECTIVE: Our aim was to conduct a systematic examination of cutaneous appendageal tumors arising in recipients of organ transplants compared with individuals who were immunocompetent (ICP). METHODS: We conducted a retrospective, clinicopathologic analysis of consecutive appendageal tumors arising in 650 recipients of organ transplants and in the general population of approximately 605,000 people served by our institution. RESULTS: Between 1993 and 1998, 231 appendageal tumors were identified in 211 individuals; 23 tumors were found in 21 of 650 patients undergoing transplant (3%), 10 in individuals with other immunosuppressive conditions, 3 in 2 patients with Muir-Torre syndrome, and 195 in 178 apparently ICP. In addition to the increased frequency of appendageal tumors among recipients of transplants, malignant tumors were overrepresented (43% of transplant tumors vs 4% in ICP; P <.0001) as were tumors of sebaceous origin (30% vs 6%; P <.0001). CONCLUSIONS: Recipients of organ transplant who are immunosuppressed have a greatly increased risk of cutaneous appendageal tumors compared with apparently ICP. In addition, their tumors are more likely to be malignant and of sebaceous origin.

Microcystic adnexal carcinoma: collaborative series review and update.

BACKGROUND: Microcystic adnexal carcinoma (MAC) is a malignant appendageal tumor first described in 1982. It can be clinically and histologically confused with other malignant and benign cutaneous neoplasms, leading to inadequate initial treatment. This neoplasm is locally aggressive and deeply infiltrating, characterized by high morbidity and frequent recurrence. Mohs micrographic surgery has been used to conserve tissue and improve the likelihood for cure. OBJECTIVE: We report our experience using Mohs micrographic surgery for the treatment of MAC and compare with earlier reports in the literature. In addition, we review the epidemiology, clinical and histologic characteristics, and optimal treatment of this rare neoplasm. We also describe a 15-year-old white male patient with MAC on the scalp occurring only 7 years after radiation exposure. METHODS: The medical records of 11 patients with MAC who were treated by Mohs micrographic surgery were reviewed at both departments, and follow-up data were obtained. RESULTS: In all patients treated with Mohs micrographic surgery, there were no recurrences after a mean follow-up of 5 years. CONCLUSION: Mohs technique enables the detection of clinically unrecognizable tumor spread and perineural invasion often encountered with MAC. Aggressive initial treatment by microscopically controlled excision appears to offer the greatest likelihood of cure for this neoplasm, while providing conservation of normal tissue. In addition, we describe the second youngest patient with MAC and readdress the issue of previous radiotherapy as an important predisposing factor.