Sebaceous carcinoma arising at a chronic candidiasis skin lesion of a patient with keratitis-ichthyosis-deafness (KID) syndrome

Impact of surgery and adjuvant treatment on the outcome of extraocular sebaceous carcinoma: a systematic review and individual patient's data analysis of 206 cases

BACKGROUND

Extraocular sebaceous carcinoma (EOSC) is an aggressive malignancy of the sebaceous gland. Surgery is considered the cornerstone of treatment, but there is lack of clarity about extent and adjuvant treatment.

METHODS

We conducted a systematic review and analysis of individual patient data of all published cases of EOSC to look into demography, pattern of care, importance of type of surgery, and other adjuvant treatment and survival outcome. A search of PubMed and Google Scholar was done with the key words sebaceous carcinoma, extraocular sebaceous carcinoma, and Muir-Torre syndrome till December 2017. The data were compiled in an Excel chart and analyzed using SPSS IBM software.

RESULTS

Data of 206 patients were retrieved. Median age at presentation was 65 years (range: 11-96 years). Surgery was performed in all except 13 patients. Of these 13, eight were deemed inoperable for extensive disease, and five had metastatic disease. Median PFS and OS for the entire cohort were 84 months (95% CI: 10-158 months) and 92 months (95% CI: 59-126 months). Univariate analysis revealed significantly poor survival for patients with a metastatic disease, regional nodal metastasis, and those with Mohs micrographic or incomplete surgery.

CONCLUSION

EOSC is a disease of elderly patients with good prognosis. Complete surgery with regional lymph node dissection is standard treatment. The role of adjuvant radiotherapy is debatable but can be considered in patients with incomplete surgery or high-risk factors.

Altered epidermal lipid processing and calcium distribution in the KID syndrome mouse model Cx26S17F

The keratitis-ichthyosis-deafness (KID) syndrome is caused by mutations in the gap junctional channel protein connexin 26 (Cx26), among them the mutation Cx26S17F. Heterozygous Cx26S17F mice resemble the human KID syndrome, i.e. exhibiting epidermal hyperplasia and hearing impairments. Newborn Cx26S17F mice show a defective epidermal water barrier as well as altered epidermal lipid secretion and location. Linoleoyl ω-esterified ceramides are strongly decreased on the skin surface of Cx26S17F mice. Moreover, the epidermal calcium gradient is altered in the mutant mice. These alterations may be caused by an abnormal Cx26S17F channel function that leads to a defective epidermal water barrier, which in turn may trigger the hyperproliferation seen in the KID syndrome.

Differential susceptibility of Cx26 mutations associated with epidermal dysplasias to peptidoglycan derived from Staphylococcus aureus and Staphylococcus epidermidis

Mutations in Connexin26 (Cx26) give rise to a spectrum of dominantly inherited hyperproliferating skin disorders, the severest being keratitis-ichthyosis-deafness (KID) syndrome, an inflammatory skin disorder, with patients prone to opportunistic infections. We compared the effects of peptidoglycan (PGN) extracted from the skin commensal Staphylococcus epidermidis and the opportunistic pathogen Staphylococcus aureus on interleukin-6 and connexin expression in HaCaT cells (a keratinocyte cell line) and connexin channel activity in HaCaT and HeLa (connexin deficient) cells transfected to express KID and non-KID Cx26 mutations. In both cell types, PGN from S. aureus induced hemichannel activity in cells expressing KID mutants as monitored by ATP release assays following 15-min challenge, while that from S. epidermidis evoked a response in HeLa cells. In KID mutant expressing cells, ATP release was significantly higher than in cells transfected with wild-type Cx26. No ATP release was observed in non-KID mutant transfected cells or in the presence of carbenoxolone, a connexin channel blocker. PGN isolated from S. aureus but not S. epidermidis induced interleukin-6 and Cx26 expression in HaCaT cells following 6-h challenge. Challenge by PGN from S. aureus evoked a greater interleukin-6 response in cells expressing KID mutants than in cells expressing wtCx26 or non-KID mutants. This response returned to basal levels if acute KID hemichannel signalling was blocked prior to PGN challenge. Thus, KID mutants form channels that can be triggered by the pro-inflammatory mediator PGN from opportunistic pathogens but not skin commensals, providing further insight into the genotype-phenotype relationship of Cx26 disorders.