Lentigo maligna: a review.

Lentigo maligna (LM) is a melanoma in situ with distinct clinical features and histology. It commonly affects men after the sixth decade of life. Incidence rates of LM have increased based on early 21st century data from different countries; however, data are suboptimal. Data from England show a plateauing crude incidence between 2013 and 2019. By comparison, invasive melanoma and other types of melanoma in situ commonly appears in younger age groups (median age 58 and 67 years old, respectively) and incidence is rising. The most important risk factors for LM include fair skin and cumulative ultraviolet solar radiation exposure. Although LM is limited to the epidermis and connected skin adnexa, it may progress to invasive LM melanoma. The reported rate of malignant progression varies, reflecting a challenge for LM epidemiology research as often lesions are removed on diagnosis. LM poses a challenge in diagnosis and management. Although it can be diagnosed clinically or dermoscopically, histopathological assessment of biopsied skin tissue remains the gold standard. Reflectance confocal microscopy allows for better appreciation of the complexity of LM at a cellular level, often progressing beyond clinical margins. Management of LM may involve Mohs micrographic surgery or excision, although recurrence may occur even with 5 mm clinical margins. Imiquimod cream may be effective, but incomplete treatment and recurrence has been reported. Conservative management with observation or radiotherapy may be used in selected patients' cases. Five-year net survival rates are excellent. This paper reviews the natural history, epidemiology, aetiology, pathogenesis, diagnosis and management of LM.

Epidemiology of porocarcinoma in England 2013-2018: a population-based registry study.

BACKGROUND: Porocarcinoma (PC) is a cutaneous malignancy that differentiates towards (possibly arises from) the sweat ducts and glands. Lack of histological diagnostic markers makes clinical and pathological diagnosis complex. The limited data available suggest the incidence is increasing; however, this remains to be established in national epidemiological studies. OBJECTIVES: To report the incidence, treatment and survival of patients with PC in England from 1 January 2013 to 31 December 2018 using national cancer registry data. METHODS: PC diagnoses in England during 2013-2018 were identified from the National Disease Registration Service using morphology and behaviour codes. These were registered from routinely collected pathology reports and cancer outcomes and services datasets. The 2013 European age standardized incidence rates (EASRs), Kaplan-Meier all-cause survival and log-rank test were calculated. RESULTS: In total, 738 tumours (396 in males and 342 in females) were diagnosed. The median age at diagnosis was 82 years old (interquartile range 74-88). The most frequently affected site were lower limbs (35.4%), followed by the face (16%). The majority of the cohort received surgical excision (73.0%). The Kaplan-Meier all-cause survival was 45.4% at 5 years, which was lower than in previous studies. The EASR for the whole population was 0.25 [95% confidence interval (CI) 0.23-0.27] per 100 000 person-years (PY)]. PC incidence rates in the East of England (EASR of 0.54, 95% CI 0.47-0.63 per 100 000 PY) were three times higher than the South West (EASR of 0.14, 95% CI 0.10-0.19 per 100 000 PY) where the regional rates were the lowest. CONCLUSIONS: This study shows that there is large variation in the EASRs of PC across England. This may reflect differences in how PC is diagnosed and registered in different regions in England. These data support national assessment of the management of PC, which will inform future studies and guideline development.

Porocarcinoma: a review.

From the first report in 1969 to the present day, diagnosis of eccrine porocarcinoma, also known simply as porocarcinoma (PC), remains a challenge. This review presents a concise update of the history, pathogenesis, epidemiology, diagnosis, management and prognosis of this rare sweat gland neoplasm. PC differentiates towards the intraepidermal spiral ducts in the eccrine gland, is more common in people aged > 60 years and often affects the head, neck and legs. PC presents as a dome-shaped papule, plaque or nodule growing over weeks to months. The exact incidence of PC is unknown but appears to be rising. Diagnosis is difficult because of variable presentations and similar clinical and histological features to cutaneous squamous cell carcinoma. Management involves removal of the tumour, usually using wide local excision or Mohs micrographic surgery. Prognosis is poor, with PC recurring after surgery in 35% of cases. Given the lack of standardized protocols and risk profiles, further studies would help improve the understanding of PC.