Sebaceous carcinoma. Tumor progression through mutational inactivation of p53

Prevalence of human papillomavirus in eyelid carcinoma among Koreans: a clinicopathological study

BACKGROUND

Human papillomavirus (HPV) has been detected in eyelid sebaceous gland carcinoma (SGC) and squamous cell carcinoma (SCC), and detection rates greatly varied across studies. This study aimed to investigate the presence of HPV in eyelid SGC and SCC among Koreans and its correlation with clinicopathological characteristics.

METHODS

Surgically resected eyelid samples diagnosed as SGC or SCC from January 1999 to June 2011 were identified from the pathology database of three referral centres in Korea. Clinicopathological information including origin (skin vs. tarsal conjunctiva) and treatment outcomes were retrospectively reviewed. Immunohistochemistry (IHC) for p16, HPV DNA in situ hybridisation (ISH), and polymerase chain reaction-based DNA microarray were performed in paraffin-embedded tissue sections.

RESULTS

Our cohort included 34 SGC and 12 SCC cases with Asian ethnicity. HPV was detected in 4 SGC and 6 SCC by DNA microarray, while 2 SCC (16.7%) showed positivity in ISH. SCC of tarsal conjunctival origin was significantly more common in HPV-positive SCC than in HPV-negative SCC (5 of 6 vs. 0 of 6, P = 0.015, Fisher's exact test). Among samples showing positive staining in p16 IHC, HPV positivity rates were 0.0% (0/19) in SGC and 100% (3/3) in SCC. There was no significant difference in overall and local recurrence rate in eyelid SGC and SCC according to the HPV status (P > 0.99).

CONCLUSIONS

HPV was found in a subset of eyelid SGC and SCC among Koreans and might be aetiologically related to SCC of tarsal conjunctival origin. Overexpression of p16 is considered to be inappropriate as an indicator of HPV infection in eyelid SGC. Further investigation is required to elucidate the transmission route and pathogenic roles of HPV.

Stratifin in ocular surface squamous neoplasia and its association with p53

PURPOSE

Sunlight-induced p53 mutations are known to contribute towards increased risk of ocular surface squamous neoplasia (OSSN). Stratifin (14-3-3σ)/HEM (human epithelial marker) is a p53-mediated inhibitor of cell cycle progression and has been shown to be a target of epigenetic deregulation in various carcinomas. In the present study, Stratifin expression, its promoter methylation status as well as expression of mutant p53 in early and advanced AJCC stages (8th edition) of OSSN, was evaluated.

METHODS

Sixty-four OSSN [20 conjunctival intraepithelial neoplasia (CIN) and 44 squamous cell carcinoma (SCC)] patients were registered for this study, and they were followed up for 36-58 months (mean 48 ± 3.6). Immunoexpression of Stratifin and mutant p53 protein, mRNA expression of Stratifin by reverse transcription polymerase chain reaction (PCR) and methylation status of Stratifin by methylation-specific PCR, was undertaken.

RESULTS

Hypermethylation of Stratifin promoter in 63% (40/64), loss of Stratifin expression in 75% (48/64) and downregulation of Stratifin mRNA in 61% (39/64) were observed. Stratifin hypermethylation was significantly associated with reduced disease-free survival in both early and advanced T stage SCC cases. Expression of mutant p53 expression was seen in 48% (31/64) OSSN cases. Of the 31 patients with mutant p53 expression, 87% (27/31) also demonstrated loss of Stratifin immunoexpression. A significant association was seen between mutant p53 expression and Stratifin loss (p = 0.01) in advanced T stage SCC cases.

CONCLUSIONS

Hypermethylation of Stratifin gene and its reduced mRNA expression both are potential biomarkers for identifying high-risk OSSN patients. Aberrant methylation of Stratifin and simultaneous mutant p53 expression implicates involvement of p53-Stratifin mediated signalling pathway in the pathogenesis of OSSN.

NGS Analysis Confirms Common TP53 and RB1 Mutations, and Suggests MYC Amplification in Ocular Adnexal Sebaceous Carcinomas

Ocular adnexal (OA) sebaceous carcinomas generally demonstrate more aggressive clinical and histopathological phenotypes than extraocular cases, but the molecular drivers implicated in their oncogenesis remain poorly defined. A retrospective review of surgical and ocular pathology archives identified eleven primary resection specimens of OA sebaceous carcinomas with adequate tissue for molecular analysis; two extraocular cases were also examined. Next-generation sequencing was used to evaluate mutations and copy number changes in a large panel of cancer-associated genes. Fluorescence in situ hybridization (FISH) confirmed MYC copy number gain in select cases, and immunohistochemistry to evaluate MYC protein expression. The commonest mutations occurred in TP53 (10/13) and RB1 (7/13). Additional mutations in clinically actionable genes, or mutations with a frequency of at least 25%, included the NF1 (3/12), PMS2 (4/12), ROS1 (3/12), KMT2C (4/12), MNX1 (6/12), NOTCH1 (4/12), PCLO (3/12), and PTPRT (3/12) loci. Low level copy number gain suggestive of amplification of the MYC locus was seen in two cases, and confirmed using FISH. MYC protein expression, as assessed by immunohistochemistry, was present in almost all sebaceous carcinoma cases. Our findings support the concept that alterations in TP53 and RB1 are the commonest alterations in sebaceous carcinoma, and suggest that MYC may contribute to the oncogenesis of these tumors.

Human Papillomavirus Related Neoplasia of the Ocular Adnexa

Human papillomaviruses (HPV) are a large group of DNA viruses that infect the basal cells of the stratified epithelium at different anatomic locations. In the ocular adnexal region, the mucosa of the conjunctiva and the lacrimal drainage system, as well as the eyelid skin, are potential locations for HPV-related neoplasia. The role of HPV in squamous cell neoplasia of the ocular adnexa has been debated for several decades. Due to the rarity of all these tumors, large studies are not available in the scientific literature, thereby hampering the precision of the HPV prevalence estimates and the ability to conclude. Nevertheless, increasing evidence supports that defined subsets of conjunctival papillomas, intraepithelial neoplasia, and carcinomas develop in an HPV-dependent pathway. The role of HPV in squamous cell tumors arising in the lacrimal drainage system and the eyelid is still uncertain. Further, the potential of HPV status as a diagnostic, prognostic, or predictive biomarker in these diseases is a topic for future research.

Molecular Genetics of Sebaceous Neoplasia

Sebaceous neoplasia primarily includes sebaceous adenoma, sebaceoma, and sebaceous carcinoma (SC). Sebaceous adenoma, sebaceoma, and a subset of cutaneous SC are frequently associated with defective DNA mismatch repair resulting from mutations in MLH1, MSH2, or MSH6. These tumors can be sporadic or associated with Muir-Torre syndrome. SCs without defective DNA mismatch repair have ultraviolet signature mutation or paucimutational patterns. Ocular SCs have low mutation burdens and frequent mutations in ZNF750. Some ocular sebaceous carcinomas have TP53 and RB1 mutations similar to cutaneous SC, whereas others lack such mutations and are associated with human papilloma virus infection.

Diagnosis and analysis of a sebaceous gland tumour of the external acoustic meatus in a Cocker Spaniel dog

Sebaceous gland tumour (SGT) is a rare tumour with a low incidence rate, which mainly occurs in the eyelid and periocular sebaceous gland. In 2019, our laboratory received a case involving a sebaceous gland tumour of the external auditory meatus for pathological diagnosis. It is a rare malignant tumour in the whole body. Data regarding a sebaceous gland tumour in the dogís external auditory meatus are few. This case is instructive for veterinary diagnosis and treatment. The dog recovered well after surgery at the outpatient department, and no recurrence was observed in the follow-up visit one year later. This study will help the identification of SGT in Spaniel dogs.

High-risk human papillomavirus and ZEB1 in ocular adnexal sebaceous carcinoma

BACKGROUND

Ocular adnexal (OA) sebaceous carcinoma is an aggressive malignancy. Oncologic drivers of ocular sebaceous carcinoma are incompletely understood.

METHODS

A retrospective search of our pathology archives for OA sebaceous carcinoma identified 18 primary resection specimens. Immunohistochemistry for p16 and ZEB1 and RNA in situ hybridization for high-risk human papillomavirus (HPV) subtypes were performed.

RESULTS

High-risk HPV was demonstrated in 2/11 (18%) cases. p16 overexpression was observed in 10/11 (91%). No association between gender, age at presentation, tumor location, intraepithelial spread, tumor size, and T stage was observed between HPV-driven and nonviral cases. High expression of ZEB1 was observed in the intraepithelial component of 4/14 (28%) cases and in the subepithelial component of 1/13 (7%) cases. ZEB1 overexpression was not associated with HPV status, T stage, or tumor size.

CONCLUSION

As previously described by others, our findings suggest that a subset of OA sebaceous carcinomas may arise via an HPV-dependent pathway. However, unlike high-risk HPV-driven carcinomas of the oropharynx, we did not identify an association between HPV-status and prognostic features. Furthermore, p16 expression was not a useful surrogate marker for HPV-driven disease. ZEB1 overexpression is not associated with HPV in our cohort of ocular sebaceous carcinoma.

Sebaceous Carcinoma Incidence and Survival Among Solid Organ Transplant Recipients in the United States, 1987-2017

Importance

Risk of sebaceous carcinoma (SC), a rare skin cancer associated with Muir-Torre syndrome, is elevated among solid organ transplant recipients (SOTRs). However, population studies evaluating this association and assessing survival for posttransplant cases are lacking, and further understanding of SC epidemiology in this immunosuppressed population could provide etiologic and clinical insights.

Objective

To assess SC incidence and patient survival after solid organ transplantation.

Design, Setting, and Participants

This cohort study, conducted from January 1, 1987, to December 31, 2017, used data from the Transplant Cancer Match Study, which links transplant and cancer registry data for 17 states and 1 metropolitan area in the United States. Altogether, these registries account for approximately 46% of all US transplants. Data on demographic and transplant characteristics as well as induction and initial maintenance immunosuppressive therapies were obtained from the transplant registry. Standardized incidence ratios (SIRs) comparing SC incidence among SOTRs to the general population were calculated. Incidence rate ratios (IRRs) comparing SC risk between SOTR subgroups were calculated using multivariate Poisson regression. Cox regression was used to compare overall survival between SC cases in SOTRs and other individuals.

Main Outcomes and Measures

Sebaceous carcinoma incidence and overall patient survival after transplantation compared with the general population.

Results

A total of 326 282 transplant procedures were performed for 301 075 patients (No. [%] age at transplant, 126 550 [38.8%] aged 0-44 years; 82 394 [25.3%] aged 45-54 years; 82 082 [25.5%] aged 55-64 years; 35 256 [10.8%] aged ≥65 years; 201 354 male patients [61.7%]; 202 557 White patients [62.1%]). A total of 102 SCs were diagnosed in 301 075 SOTRs, corresponding to a 25-fold increased incidence (SIR, 24.8; 95% CI, 20.2-30.1). Incidence was especially elevated among lung recipients (SIR, 47.7; 95% CI, 20.6-94.0) and after a posttransplant diagnosis of cutaneous squamous cell carcinoma (SIR, 104.0; 95% CI, 62.8-163.0). Among SOTRs, factors independently associated with SC risk included male sex (IRR, 2.46; 95% CI, 1.48-4.07; P < .001), race/ethnicity (non-Hispanic Black vs non-Hispanic White, IRR, 0.28; 95% CI, 0.10-0.77; P = .01), older age (IRR, 7.85; 95% CI, 3.85-16.0; ≥65 vs 0-44 years; P < .001 for trend), use of thymoglobulin induction (IRR, 1.82; 95% CI, 1.16-2.86; P = .009), posttransplant cutaneous squamous cell carcinoma (IRR, 4.60; 95% CI, 2.67-7.94; P < .001), and longer time since transplant (IRR, 8.40; 95% CI, 3.94-17.90; ≥10 vs 0-1.9 years; P < .001 for trend). Muir-Torre syndrome-associated cancers were rare among both SOTRs and others with SC (3.3%-4.1%). Among patients with SC, prior transplantation was associated with increased overall mortality (adjusted hazard ratio, 2.09; 95% CI, 1.45-3.01), although few deaths were attributed to SC (4 of 92 SOTRs [4.3%]; 235 of 3585 non-SOTRs [6.6%]).

Conclusions and Relevance

Among SOTRs, results of this large cohort study suggest that SC was associated with measures of immunosuppression, and overall survival was worse than for other patients with SC. Findings also suggest a possible role for UV radiation in carcinogenesis.

Sebaceous Carcinoma Epidemiology and Genetics: Emerging Concepts and Clinical Implications for Screening, Prevention, and Treatment

Sebaceous carcinoma is an aggressive skin cancer with a 5-year overall survival rate of 78% for localized/regional disease and 50% for metastatic disease. The incidence of this cancer has been increasing in the United States for several decades, but the underlying reasons for this increase are unclear. In this article, we review the epidemiology and genetics of sebaceous carcinoma, including recent population data and tumor genomic analyses that provide new insights into underlying tumor biology. We further discuss emerging evidence of a possible viral etiology for this cancer. Finally, we review the clinical implications of recent advances in sebaceous carcinoma research for screening, prevention, and treatment.

Human papillomavirus in ocular malignant tumours: a study from a tertiary eye care centre in North India

OBJECTIVE

The present study aims to detect the presence of human papillomavirus (HPV) in ocular malignant tumours, including retinoblastoma, eyelid squamous cell carcinoma (SCC), and sebaceous gland carcinoma (SGC), in the North Indian population.

DESIGN

Prospective observational non randomized study.

PARTICIPANTS

In this study, 142 prospective cases of ocular malignant tumours (retinoblastoma, SGC, and SCC) were included.

METHODS

HPV was detected by multiplex PCR using PGMY09/11 primers in 142 patients with ocular malignancies. This was followed by genotyping using linear array (reverse hybridization).

RESULTS

Of the 142 tumours studied, 72 were retinoblastoma, 30 SGC, and 40 SCC. The HPV genome was detected in 2.8% (4 of 142) of cases by multiplex PCR; all positive cases (4 of 40) were SCC. Genotyping revealed that all positives belonged to the high-risk HPV16 genotype. HPV-positive SCC patients had better disease-free survival. Retinoblastoma and SGC cases were negative for HPV.

CONCLUSIONS

Low prevalence of HPV in ocular malignancies was observed in this study. The HPV genome was detected only in ocular squamous cell carcinoma cases and these patients were associated with better prognosis. HPV may not have a role in retinoblastoma and SGC in the North Indian population.

Next-generation sequencing identifies high frequency of mutations in potentially clinically actionable genes in sebaceous carcinoma

Sebaceous carcinoma (SC) is a rare but aggressive malignancy with frequent recurrence and metastases. Surgery is the mainstay of therapy, but effective systemic therapies are lacking because the molecular alterations driving SC remain poorly understood. To identify these, we performed whole-exome next-generation sequencing of 409 cancer-associated genes on 27 SCs (18 primary/locally recurrent ocular, 5 paired metastatic ocular, and 4 primary extraocular) from 20 patients. In ocular SC, we identified 139 non-synonymous somatic mutations (median/lesion 3; range 0-23). Twenty-five of 139 mutations (18%) occurred in potentially clinically actionable genes in 6 of 16 patients. The most common mutations were mutations in TP53 (n = 9), RB1 (n = 6), PIK3CA (n = 2), PTEN (n = 2), ERBB2 (n = 2), and NF1 (n = 2). TP53 and RB1 mutations were restricted to ocular SC and correlated with aberrant TP53 and RB protein expression. Systematic pathway analyses demonstrated convergence of these mutations to activation of the PI3K signalling cascade, and PI3K pathway activation was confirmed in tumours with PTEN and/or PIK3CA mutations. Considerable inter-tumoural heterogeneity was observed between paired primary and metastatic ocular SCs. In primary extraocular SC, we identified 77 non-synonymous somatic mutations (median/lesion 22.5; range 3-29). This overall higher mutational load was attributed to a microsatellite instability phenotype in three of four patients and somatically acquired mutations in mismatch repair genes in two of four patients. Eighteen of 77 mutations (23%) were in potentially clinically actionable genes in three of four patients, including BTK, FGFR2, PDGFRB, HRAS, and NF1 mutations. Identification of potentially clinically actionable mutations in 9 of 20 SC patients (45%) underscores the importance of next-generation sequencing to expand the spectrum of genotype-matched targeted therapies. Frequent activation of PI3K signalling pathways provides a strong rationale for application of mTOR inhibitors in the management of this disease. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

p16 Expression Is Not a Surrogate Marker for High-Risk Human Papillomavirus Infection in Periocular Sebaceous Carcinoma

PURPOSE

To evaluate the role of high-risk human papillomavirus (HR-HPV) infection in periocular sebaceous carcinoma (SC) using multiple methods of detection, and to determine whether p16 overexpression is present and can be used as a surrogate marker for HR-HPV.

DESIGN

Retrospective observational case series with laboratory investigations.

METHODS

Unstained paraffin sections of 35 cases of periocular SC were analyzed with immunohistochemistry for p16 and subjected to polymerase chain reaction (PCR) for HR-HPV. A subset of 18 lesions that were p16-positive was further studied with a novel method of mRNA in situ hybridization (ISH) for the detection of transcriptionally active HR-HPV, an advanced technique with an enhanced sensitivity and specificity.

RESULTS

The clinical findings were in keeping with those of comparable earlier studies. Strong immunohistochemical p16 positivity (meeting the criterion of >70% nuclear and cytoplasmic staining) was present in 29 of 35 cases of periocular SC (82.9%). The selected 18 p16-positive cases tested were negative for HR-HPV using mRNA ISH. PCR yielded unequivocal results with adequate DNA isolated in 24 cases, 23 of which were negative for HR-HPV. One case was positive for HPV type 16, which was found to be a false positive as collaterally determined by mRNA ISH negativity.

CONCLUSION

No evidence was found for HR-HPV as an etiologic agent in the development of periocular SC using multiple modalities to maximize sensitivity and specificity and reduce the limitations of any single test. p16 overexpression is common in periocular SC but unrelated to HR-HPV status. Although p16 may be used as a surrogate marker for HR-HPV status in other tissue sites, this interpretation of p16 positivity is not applicable to periocular SC.

Circumscribed sebaceous neoplasms: a morphological, immunohistochemical and molecular analysis

Sebaceous neoplasms encompass a range of lesions, including benign entities such as sebaceous adenoma and sebaceoma, as well as sebaceous carcinoma. The distinction of sebaceous carcinoma from benign lesions relies on histological identification of architectural or cytological features of malignancy. In this study we have assessed the diagnostic discriminatory ability of mitotic rate and immunohistochemical markers (p53, bcl-2 and p16) in a selected group of well circumscribed sebaceous neoplasms, incorporating examples of sebaceous adenoma, sebaceoma and sebaceous carcinoma. We found that mitotic rate was significantly higher in malignant lesions as compared to benign lesions, but none of the immunohistochemical markers showed a discriminatory expression pattern. In addition, we performed a mutational analysis on the same group of lesions using next generation sequencing (NGS) technology. The most commonly mutated gene was TP53, although there was no correlation between the p53 immunohistochemical results and number or type of TP53 mutation detected. CDKN2A, EGFR, CTNNB1 and KRAS were also commonly mutated across all lesions. No particular gene, mutation profile or individual mutation could be identified which directly correlated with the consensus histological diagnosis. In conclusion, within this diagnostically challenging group of lesions, mitotic activity, but not immunohistochemical labelling for p16 or bcl-2, correlates with diagnostic category. While a number of genes potentially involved in the genesis of sebaceous neoplasia were uncovered, any molecular differences between the histological diagnostic categories remain unclear.

Updates on the Molecular Pathology of Selected Ocular and Ocular Adnexal Tumors: Potential Targets for Future Therapy

Ophthalmic pathologic studies of retinoblastoma first definitively elucidated a genetic etiology for cancer three decades ago. Advances in DNA sequencing, protein expression profiling, and the exploration of epigenetics have since led to categorization of tumors and clinical prognostication based on genetic aberrancy. There are now many neoplasms that are defined by a characteristic genetic signature. In the past several years alone, much has been discovered in regard to the original tumor-suppressor gene initially defined in retinoblastoma as well as in other intraocular tumors such as medulloepithelioma. Our further understanding of ocular adnexal tumors that result in substantial morbidity and mortality, such as sebaceous carcinoma, has also benefited from a genetic approach. In this article, we review the clinicopathologic features of the foregoing three entities--retinoblastoma, medulloepithelioma, and sebaceous carcinoma--in order to highlight discoveries in their underlying abnormal molecular genetic functioning.

Differential senescence capacities in meibomian gland carcinoma and basal cell carcinoma

Meibomian gland carcinoma (MGC) and basal cell carcinoma (BCC) are common eyelid carcinomas that exhibit highly dissimilar degrees of proliferation and prognoses. We address here the question of the differential mechanisms between these two eyelid cancers that explain their different outcome. A total of 102 confirmed MGC and 175 diagnosed BCC cases were analyzed. Twenty confirmed MGC and twenty diagnosed BCC cases were collected to determine the telomere length, the presence of senescent cells, and the expression levels of the telomere capping shelterin complex, P53, and the E3 ubiquitin ligase Siah1. Decreased protein levels of the shelterin subunits, shortened telomere length, over-expressed Ki-67, and Bcl2 as well as mutations in P53 were detected both in MGC and BCC. It suggests that the decreased protein levels of the shelterin complex and the shortened telomere length contribute to the tumorigenesis of MGC and BCC. However, several parameters distinguish MGC from BCC samples: (i) the mRNA level of the shelterin subunits decreased in MGC but it increased in BCC; (ii) P53 was more highly mutated in MGC; (iii) Siah1 mRNA was over-expressed in BCC; (iv) BCC samples contain a higher level of senescent cells; (v) Ki-67 and Bcl2 expression were lower in BCC. These results support a model where a preserved P53 checkpoint in BCC leads to cellular senescence and reduced tumor proliferation as compared to MGC.

Sebaceous carcinoma: review of the literature

BACKGROUND

Sebaceous carcinoma is an uncommon adnexal neoplasm with a documented capability for regional and distant metastasis. Traditionally, sebaceous carcinoma has been associated with high rates of recurrence after excision.

OBJECTIVE

To review the current literature on sebaceous carcinoma and detail its epidemiology, pathogenesis, clinical presentation, histopathology, diagnostic workup, treatment, and prognosis.

MATERIALS AND METHODS

Literature review using PubMed search for articles related to sebaceous carcinoma.

RESULTS

Sebaceous carcinoma typically presents as a painless pink or yellow nodule. Diagnosis requires histopathologic examination, and immunohistochemical analysis often assists in the differentiation of sebaceous carcinoma from other benign and malignant skin neoplasms. Sebaceous carcinoma should prompt a workup for Muir-Torre syndrome. Periorbital sebaceous carcinoma has an increased tendency for regional metastasis, although cancer-specific mortality rates are similar among all anatomic locations.

CONCLUSION

Surgery is the preferred treatment for local disease. Limited data suggest that Mohs micrographic surgery may provide superior clinical outcomes, but more research is needed regarding the long-term outcomes. Radiation and systemic chemotherapy are reserved for recurrent or metastatic disease.

Periocular sebaceous gland carcinoma: do androgen receptor (NR3C4) and nuclear survivin (BIRC5) have a prognostic significance?

PURPOSE

The study aimed at evaluating the expression of androgen receptor (AR) and nuclear survivin (NS) in periocular sebaceous gland carcinoma (SGC) and to determine whether this expression is associated with histopathological features, markers of apoptosis and proliferation and with clinical outcomes.

METHODS

This was a retrospective, comparative case series which included 56 patients with a biopsy-proven periocular SGC. Immunohistochemical staining for AR, survivin, p53 and Ki-67 was analysed in all cases.

RESULTS

All patients expressed AR, p53 and Ki-67 in the nucleus of tumour cells. Twenty-four patients (42.8%) had a high AR score, and 32 patients (57.2%) had a low AR score. Twenty-four (42.8%) patients expressed survivin in the nucleus of tumour cells. Nine (37.5%) had a high NS score, and 15 (62.5%) had a low NS score. Patients with a high AR score had a greater recurrence (p < 0.005), higher expression of Ki-67 (p < 0.0001) and a lower p53 expression (p < 0.005). Nuclear expression of survivin correlated with a high Ki-67 labelling index (0.0001) and low p53 expression (<0.005). Neither nuclear expression of survivin nor the NS score correlated with any clinicopathological features.

CONCLUSION

Expression of AR significantly impacts prognosis and is thus promising prognostic marker in periocular SGC.

Comparison of HER2 gene amplification and KRAS alteration in eyelid sebaceous carcinomas with that in other eyelid tumors

Eyelid sebaceous carcinoma (SC) represents a highly aggressive malignancy. Despite the poor prognosis, genetic alterations as potential molecular targets are not available. KRAS mutation and HER2 gene amplification may be candidates related to their genetic alterations. We examined the HER2 and KRAS alteration status in eyelid SCs and compared it with that in other eyelid tumors. The controversial topics of the human papillomavirus (HPV) and p16 expression were also investigated. HER2 amplification was determined by silver in situ hybridization, while immunohistochemistry was performed to study protein expressions in 14 SCs and controls, including 23 other eyelid malignancies and 14 benign tumors. Peptide nucleic acid-mediated PCR clamping and direct sequencing were used to detect KRAS mutations. HER2 protein overexpression was observed in 85.7% (12/14) of the SCs, of which two-thirds showed HER2 gene amplification. HER2 protein overexpression and HER2 amplification were found more frequently in eyelid SCs than in other eyelid tumors. All SCs harbored wild type KRAS genes. No HPV infections were identified in the SCs. Nevertheless, p16 overexpression was found in 71.4% (10/14) of SCs, irrespective of the status of HPV infection. Furthermore, p16 overexpression in eyelid SCs was also significantly higher than that in other eyelid tumors. HER2 protein overexpression, HER2 gene amplifications, and wild type KRAS genes are common in eyelid SCs. HER2 gene amplification may represent potential therapeutic targets for the treatment of eyelid SCs.

Molecular pathology of skin neoplasms of the head and neck

CONTEXT

Skin neoplasms include the most common malignancies affecting humans. Many show an ultraviolet (UV)-induced pathogenesis and often affect the head and neck region.

OBJECTIVE

To review literature on cutaneous neoplasms that show a predilection for the head and neck region and that are associated with molecular alterations.

DATA SOURCES

Literature review.

CONCLUSIONS

Common nonmelanoma skin cancers, such as basal and squamous cell carcinomas, show a UV-induced pathogenesis. Basal cell carcinomas are characterized by molecular alterations of the Hedgehog pathway, affecting patched and smoothened genes. While squamous cell carcinomas show UV-induced mutations in several genes, driver mutations are only beginning to be identified. In addition, certain adnexal neoplasms also predominantly affect the head and neck region and show interesting, recently discovered molecular abnormalities, or are associated with hereditary conditions whose molecular genetic pathogenesis is well understood. Furthermore, recent advances have led to an increased understanding of the molecular pathogenesis of melanoma. Certain melanoma subtypes, such as lentigo maligna melanoma and desmoplastic melanoma, which are more often seen on the chronically sun-damaged skin of the head and neck, show differences in their molecular signature when compared to the other more common subtypes, such as superficial spreading melanoma, which are more prone to occur at sites with acute intermittent sun damage. In summary, molecular alterations in cutaneous neoplasms of the head and neck are often related to UV exposure. Their molecular footprint often reflects the histologic tumor type, and familiarity with these changes will be increasingly necessary for diagnostic and therapeutic considerations.

Eyelid sebaceous carcinoma: clinicopathologic and multiparametric immunohistochemical analysis that includes adipophilin

PURPOSE

To evaluate the fine cytopathologic features and immunohistochemistry of eyelid sebaceous carcinoma.

DESIGN

Retrospective clinicopathologic study.

METHODS

Clinical records and microscopic glass slides of 12 patients diagnosed with sebaceous carcinoma were reviewed. Paraffin-embedded tissue recuts were immunoreacted for epithelial membrane antigen (EMA), Ber-EP4, p53, Ki-67, and adipophilin for cytoplasmic lipid. Invasive growth and intraepithelial spread were analyzed separately. Cytoplasmic and nuclear characteristics were correlated with the results of the immunohistochemical profiling.

RESULTS

Five patients experienced recurrences, but no metastases or tumor-related deaths were discovered. The nuclei in 11 invasive tumor cells were typically round with finely divided, granular, or smudgy chromatin without prominent margination at the nuclear membrane; they exhibited small punctate nucleoli. Positivity for EMA (both diffuse and focal), p53 (72% of nuclei), and Ki-67 (45% proliferation index) was demonstrated. Adipophilin positivity in vesicular and granular forms was detected in paraffin sections in all invasive tumors, most prominently in moderately differentiated and well-differentiated lesions. Among 9 cases exhibiting intraepithelial extensions, 6 showed mostly granular positivity and 3 vesicular positivity. p53 identified residual atypical intraepithelial cells when conjunctival epithelial sloughing occurred.

CONCLUSIONS

Immunohistochemistry can make significant contributions to the diagnosis of sebaceous carcinoma. p53 and vesicular granular adipophilin positivity were highly reliable in supplementing the routine microscopic diagnosis of infiltrative tumors and both can be used in paraffin sections, thereby obviating cumbersome oil red O staining of frozen sections. The cells found in intraepithelial spread were strongly EMA and p53 positive, with more granular than vesicular adipophilin positivity.

Expression of cell cycle regulatory proteins in eyelid sebaceous gland carcinoma: low p27 expression predicts poor prognosis

Prognosis of eyelid sebaceous gland carcinoma is largely unpredictable and there are few practically available markers for predicting patients' prognosis. Dysregulation of cell cycle progression is strongly associated with the development of cancer and the cancer prognosis. We investigated the expression of cell cycle regulatory proteins in eyelid sebaceous gland carcinoma and estimate their value as prognostic predictors. Forty-three cases of eyelid sebaceous gland carcinoma were included in this study. Immunohistochemistry for the p53, p21, p27, cyclin E, p16, cyclin D1, and phosphorylated Rb (pRb) proteins was performed using archival paraffin blocks. Correlations between clinical features and protein expression were evaluated statistically. Nine patients showed lymph node or distant metastasis, and the remaining patients showed localized disease. High expression of p21, p27, cyclin E, and p16 was found in the majority of tumor cell nuclei, whereas these proteins were rarely expressed in the normal sebaceous glands. However, pRb was focally lost in a subset of cases. Patients showing diffuse p27 expression developed metastasis less commonly than those with negative or focal p27 expression (log-rank test, p = 0.008). Aberrant expression of cell cycle regulatory proteins was observed in eyelid sebaceous gland carcinoma, suggesting that cell cycle dysregulation is involved in the pathogenesis of this tumor. Decreased p27 expression is a predictive biomarker of an unfavorable prognosis of eyelid sebaceous gland carcinoma.

Hypermethylation of the CDKN2A gene promoter is a frequent epigenetic change in periocular sebaceous carcinoma and is associated with younger patient age

Periocular sebaceous carcinoma is an aggressive neoplasm with significant morbidity and mortality. Its pathogenesis is poorly understood. It is only rarely associated with Muir-Torre syndrome. Previous studies from Asian countries, have suggested that human papillomavirus (HPV) infection plays a role in the pathogenesis and overexpression of p16(INK4a), a surrogate marker of HPV infection, have also been reported. However, data from western countries seem contradictory. In order to clarify and explore the molecular and epigenetic basis of HPV, CDKN2A status and role of microsatellite instability in the development of periocular sebaceous carcinoma, 24 cases of periocular sebaceous carcinoma were analyzed for the expression of p16(INK4a) and mismatch repair proteins (MLH1, MSH2, MSH6 and PMS2) via immunohistochemistry. Nested polymerase chain reaction (PCR) and genechip HPV typing were used to detect HPV infection and decide its genotype when present. PCR amplification using a consensus primer pair was also performed to detect β-HPV. The methylation status of CDKN2A promoter region was studied by methylation-specific polymerase chain reaction. HPV-positivity was demonstrated in only one of our cases (HPV 16), while another case showed p16(INK4a) overexpression. All cases showed preserved expression of mismatch repair proteins. CDKN2A promoter hypermethylation was noted in nearly half of our cases (11/24) and was associated with younger patient age (P = .013). Our results showed that periocular sebaceous carcinoma is rarely associated with HPV and microsatellite instability. Higher frequency of CDKN2A promoter hypermethylation in younger patients implies a significant epigenetic role in tumor development in this age group.

p53 staining correlates with tumor type and location in sebaceous neoplasms

Sebaceous neoplasms are commonly considered in their relationship to the Muir-Torre syndrome and the now well-documented loss of DNA mismatch repair proteins leading to microsatellite instability. However, sebaceous neoplasms showing microsatellite instability comprise only a subset of this group of tumors, and thus, alternative tumorigenic mechanisms must exist. This article explores the relationship of p53, a tumor suppressor implicated in other cutaneous malignancies, and sebaceous neoplasia. We examined 94 sebaceous tumors from 92 patients. Tumors with strong nuclear p53 staining were significantly associated with the diagnosis of sebaceous carcinoma compared with benign sebaceous lesions, most notably for periocular carcinomas. Importantly, nuclear mismatch repair protein expression was intact in all lesions showing p53 alterations, suggesting that p53 dysfunction may represent a divergent pathway in the molecular pathogenesis of these tumors.

Early onset sebaceous carcinoma

BACKGROUND

Ocular sebaceous carcinoma can masquerade as benign lesions resulting in delay of diagnosis. Early recognition is even more difficult in young patients where the disease rarely occurs. Here, we provide a clinicopathological correlation of ocular sebaceous carcinoma in a young individual lacking history of hereditary cancer or immunosuppression.

FINDINGS

A detailed histopathological study including p53 DNA sequencing was performed on an aggressive sebaceous carcinoma presenting in a healthy 32 year-old Caucasian woman. She had no history of retinoblastoma, evidence for a hereditary cancer syndrome, or radiation therapy. However, she potentially was at risk for excessive UV light exposure. A detailed review of the literature is also provided.A moderately well differentiated sebaceous carcinoma was established histopathologically arising from the meibomian gland of the upper eyelid. In most areas, the cytoplasm contained small but distinct Oil-red-O positive vacuoles. Direct sequencing of p53 identified a G:C→A:T mutation at a dipyrimidine site. The mutation results in substitution of arginine for the highly conserved glycine at residue 199 located at the p53 dimer-dimer interface. Energy minimization structural modeling predicts that G199R will neutralize negative charges contributed by nearby inter- and intramonomeric glutamate residues.

DISCUSSION

This study points to the importance of recognizing that sebaceous carcinoma can occur in young patients with no evidence for hereditary cancer risk or radiation therapy. The G199R substitution is anticipated to alter the stability of the p53 tetrameric complex. The role of UV light in the etiology of sebaceous carcinoma deserves further study. Our findings, taken together with those of others, suggest that different environmental factors could lead to the development of sebaceous carcinoma in different patients.

Sebaceous neoplasia and the Muir-Torre syndrome: important connections with clinical implications

Sebaceous neoplasia comprises a spectrum ranging from benign to malignant. Proper histological identification is important for treatment, prognosis and potential association with the Muir-Torre syndrome (MTS). Our increased understanding of the significance and pathogenesis of these tumours has led to improved risk stratification, screening recommendations, and treatment of patients with an initial presentation of a sebaceous tumour. This review focuses on the diagnostic and histological features of sebaceous lesions, the MTS, and recent insights into the molecular pathogenesis of sebaceous tumours.

Adnexal skin carcinomas of the face

Skin adnexal neoplasms are rare tumors, and knowledge on their exact histological development and pathogenesis remains fragmented. Their diagnosis and management are frequently troublesome, especially for malignant tumors. We present a retrospective case series of malignant appendageal tumors of the face. Records of patients with histologically confirmed adnexal skin carcinoma managed at a single department during the period 1995 to 2004 were reviewed. Patient biodata, surgical management, and main outcome measures such as locoregional recurrence, distant metastasis, and disease-free and overall survival were recorded.Eleven patients were identified from record analysis. Lesions were mainly located at the eyelids and the nose. All patients were managed with wide local excision and restoration with local flaps. Two patients showed regional metastasis and underwent radical neck dissection. Nine of 11 patients were alive and free of local and/or regional disease on final follow-up. Two patients died of causes unrelated to the disease. Clinical and histological features, tumor biological behavior, diagnostic difficulties, and recommended management are discussed.In conclusion, adnexal skin tumors should be considered in the differential diagnosis of skin tumors, particularly in view of their more sinister prognosis compared with other nonmelanoma skin tumors. They are acknowledged to demand a more aggressive plan of surgical treatment.

Sebaceous carcinoma: the great masquerader: emgerging concepts in diagnosis and treatment

Sebaceous carcinoma (SC) is a rare tumor with a high rate of local recurrence and metastasis to lymph nodes and organs. The majority of SCs occur in the periocular region frequently presenting as painless, round subcutaneous nodules with a high tendency of diffuse and invasive growth in the eyelid and conjunctiva. It frequently masquerades as inflammatory conditions or as other tumors leading to delay in diagnosis, inappropriate treatment and increased morbidity and mortality. Sebaceous carcinoma is associated with Muir-Torre syndrome, a genetic condition presenting with sebaceous skin tumors associated with internal malignancy. Therefore, SC patients must be carefully evaluated and referred to an internist or gastroenterologist when indicated. Surgery is the definitive therapy for SC. In recent years, less radical surgical strategies are being used with improved outcomes. Current studies demonstrate that Mohs micrographic surgery (MMS) provides maximal tissue conservation and lower recurrence rates. Greater awareness and understanding of SC and its behavior has led to earlier diagnosis and appropriate treatment.

Epidemiology of nonkeratinocytic skin cancers among persons with AIDS in the United States

OBJECTIVE

Immunosuppression may increase risk for some skin cancers. We evaluated skin cancer epidemiology among persons with AIDS.

DESIGN

We linked data from population-based US AIDS and cancer registries to evaluate risk of nonkeratinocytic skin cancers (melanoma, Merkel cell carcinoma, and appendageal carcinomas, including sebaceous carcinoma) in 497 142 persons with AIDS.

METHODS

Standardized incidence ratios (SIRs) were calculated to relate skin cancer risk to that in the general population. We used logistic regression to compare risk according to demographic factors, CD4 cell count, and a geographic index of ultraviolet radiation exposure.

RESULTS

From 60 months before to 60 months after AIDS onset, persons with AIDS had elevated risks of melanoma (SIR = 1.3, 95% confidence interval 1.1-1.4, n = 292 cases) and, more strongly, of Merkel cell carcinoma (SIR = 11, 95% confidence interval 6.3-17, n = 17) and sebaceous carcinoma (SIR = 8.1, 95% confidence interval 3.2-17, n = 7). Risk for appendageal carcinomas increased with progressive time relative to AIDS onset (P trend = 0.03). Risk of these skin cancers was higher in non-Hispanic whites than other racial/ethnic groups, and melanoma risk was highest among men who have sex with men. Melanoma risk was unrelated to CD4 cell count at AIDS onset (P = 0.32). Risks for melanoma and appendageal carcinomas rose with increasing ultraviolet radiation exposure (P trend <10 and P trend = 10, respectively).

CONCLUSION

Among persons with AIDS, there is a modest excess risk of melanoma, which is not strongly related to immunosuppression and may relate to ultraviolet radiation exposure. In contrast, the greatly increased risks for Merkel cell and sebaceous carcinoma suggest an etiologic role for immunosuppression.

Distinction of Benign Sebaceous Proliferations From Sebaceous Carcinomas by Immunohistochemistry

Sebaceous lesions, including sebaceous hyperplasia, sebaceomas, and sebaceous adenomas and carcinomas, are histologically distinctive adnexal proliferations with a spectrum of biological behavior ranging from benign to frankly malignant. The histologic distinction between sebaceous adenomas and carcinomas may be challenging, especially in cases showing atypical features and in small or partial biopsies. We studied multiple oncogenic and therapeutic related proteins by immunohistochemistry to identify differences in expression between benign and malignant sebaceous proliferations. A total of 27 cases, including 9 sebaceous adenomas, 4 sebaceomas, 8 sebaceous carcinomas, and 6 cases of sebaceous hyperplasia, were examined by immunohistochemistry, with antibodies directed against Ki-67 (MIB-1), bcl-2, p53, p21WAF1, p27Kip1, c-erbB-2 (Her-2/neu), CD117 (c-kit), cyclin D1, MDM2, CD99, MLH-1, and MSH-2. We found that sebaceous adenomas and sebaceomas stained like sebaceous hyperplasia did, whereas carcinomas had statistically significantly increased levels of p53 (50% versus 11%, respectively) and Ki-67 (30% versus 10%). The carcinomas also had significantly reduced levels of bcl-2 (7% versus 56%, respectively) and p21 (16% versus 34%) compared to the adenomas. Thus, a combination of several of these markers may be diagnostically useful in challenging cases. In addition, we found little or no Her-2/neu and CD117 staining, indicating that immunotherapy with Herceptin or Gleevac would likely not be useful for sebaceous carcinomas. Moreover, these results show that sebaceous adenomas and carcinomas are distinct neoplasms and provide no support for the theory that all sebaceous adenomas are truly malignant.

In vivo direct molecular imaging of early tumorigenesis and malignant progression induced by transgenic expression of GFP-Met

The tyrosine kinase receptor Met and its ligand, hepatocyte growth factor/scatter factor (HGF/SF), play an important role in normal developmental processes, as well as in tumorigenicity and metastasis. We constructed a green fluorescent protein (GFP) Met chimeric molecule that functions similarly to the wild-type Met receptor and generated GFP-Met transgenic mice. These mice ubiquitously expressed GFP-Met in specific epithelial and endothelial cells and displayed enhanced GFP-Met fluorescence in sebaceous glands. Thirty-two percent of males spontaneously developed adenomas, adenocarcinomas, and angiosarcomas in their lower abdominal sebaceous glands. Approximately 70% of adenocarcinoma tumors metastasized to the kidneys, lungs, or liver. Quantitative subcellular-resolution intravital imaging revealed very high levels of GFP-Met in tumor lesions and in single isolated cells surrounding them, relative to normal sebaceous glands. These single cells preceded the formation of local and distal metastases. Higher GFP-Met levels correlated with earlier tumor onset and aggressiveness, further demonstrating the role of Met-HGF/SF signaling in cellular transformation and acquisition of invasive and metastatic phenotypes. Our novel mouse model and high-resolution intravital molecular imaging create a powerful tool that enables direct real-time molecular imaging of receptor expression and localization during primary events of tumorigenicity and metastasis at single-cell resolution.

Intraepithelial sebaceous carcinoma of the eyelid misdiagnosed as Bowen's disease

BACKGROUND

Sebaceous carcinoma (SC) is well known for its ability to masquerade clinically and histologically as a variety of periocular conditions resulting in a delayed diagnosis. We present a series of periocular SC cases and discuss the difficulties in histopathological diagnosis when this tumor presents with a Bowenoid pattern of intraepithelial spread.

METHODS

A retrospective case study of all patients with SC of the eyelid treated in our Hospital, from 1997 to 2004, was conducted.

RESULTS

Eight patients were identified (four females and four males). Seven cases involved the upper eyelid. Initial clinical diagnoses included blepharitis (three cases), blepharoconjunctivitis (one case), cicatrizing conjunctivitis (one case), and lid lesions (two cases). Histopathologically, 87.5% of cases were misdiagnosed as Bowen's disease (BD) on the initial biopsy. Six of these cases showed no invasive disease on the initial biopsy and were eventually found to be invasive SC on subsequent excisions. In one case, the tumor was wholly in situ. Delay in diagnosis ranged from 0 to 56 months.

CONCLUSIONS

SC should always be considered in the histological differential diagnosis of any eyelid lesion which resembles BD, particularly if the upper eyelid is involved or if multivacuolated cytoplasmic clear cell changes are seen.

Pilomatrix carcinomas contain mutations in CTNNB1, the gene encoding beta-catenin

Mutations in beta-catenin are present in benign pilomatrixomas. beta-catenin is a downstream effector in the WNT-signalling pathway, acting as a signal for differentiation and proliferation. Mutations in CTNNB1, the gene encoding beta-catenin, are present in a wide variety of benign and malignant neoplasms. We examined beta-catenin in a series of pilomatrix carcinomas (15 cases) by using immunohistochemistry and DNA sequencing of exon 3 from CTNNB1, and compared these to a series of benign pilomatrixomas (13 cases). All 11 pilomatrix carcinomas available for examination showed nuclear localization of beta-catenin and mutations in exon 3 similar to those demonstrated in benign pilomatrixomas. Two of 11 pilomatrix carcinomas showed significant nuclear accumulation of p53, whereas this was absent in all 13 benign pilomatrixomas. Expression of nuclear cyclin D1 was similar in both benign pilomatrixomas and pilomatrix carcinomas. Clinical follow-up from the 15 malignant cases reported in this study and by others indicates that wide excision offers superior control of local recurrence, compared to simple excision. Immunohistochemical and molecular analysis of beta-catenin reveals that both pilomatrix carcinomas and benign pilomatrixomas harbour mutations in beta-catenin. This implies a common initial pathogenesis and is compatible with the proposition that pilomatrix carcinomas may at least on occasion arise from their benign counterparts.

Sebaceous carcinoma of the ocular region: a review

Sebaceous carcinoma of the ocular region is a malignant neoplasm that is being recognized more frequently and managed by innovative techniques of local resection, cryotherapy, topical chemotherapy, and radiotherapy, resulting in improved visual and systemic prognosis.

Virus-induced chalazion

PURPOSE

To investigate a viral etiology in certain chalazia.

METHODS

A prospective study over 7.5 years of all newly presenting chalazia associated with diffuse follicular conjunctivitis but without any other aetiological factors. Patients were investigated for ocular or systemic infections by history, physical exam, slit-lamp exam, and/or histology of conjunctival biopsy (including transmission electron microscopy).

RESULTS

A total of 27 patients developed follicular conjunctivitis without meibomian gland dysfunction, blepharitis, or sexually transmitted diseases. Evidence for a viral aetiology included: recent systemic viral illness (15/27), recent contact with subjects with chalazia or follicular conjunctivitis (5/27), preauricular lymphadenopathy (4/27), viral corneal disease (4/27), or viral particles by ultrastructure (4/4).

CONCLUSIONS

Chalazia may be associated with viral conjunctivitis. Intralesional corticosteroids should be considered with great caution for viral-induced chalazia.

Sebaceous carcinoma and the T-antigen

Carcinomas of sebaceous glands are uncommon. They are traditionally classified into ocular and extraocular sebaceous carcinomas (SC). Ocular SC tend to be more common and more aggressive than extraocular SC. However, the latter can occasionally follow a fatal course. Histologically, SC should be classified into 1) SC in situ; 2) SC, infiltrating, low-grade with or without pagetoid spread; 3) SC, infiltrating, high-grade, with or without pagetoid spread; and 4) SC with extraocular and extracutaneous involvement, including metastases. Immunohistochemistry plays a minor role in the diagnosis of SC. Thomsen-Friedenreich (T) antigen can be a helpful tool in differentiating SC (strong T-antigen reactivity in basaloid cells) from other mimicking neoplasms (basaloid cells are T-antigen negative). The histologic differential diagnosis, pathogenesis, and management of SC are reviewed.

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.

Loss of p21(WAF1) compartmentalisation in sebaceous carcinoma compared with sebaceous hyperplasia and sebaceous adenoma

AIMS

Regulation of cell cycle progression is a fundamental control process, linked to cellular differentiation and apoptosis in normal tissues. p21(WAF1) is a nuclear protein that regulates cell cycle progression. p21(WAF1) can be transcriptionally upregulated by p53, but may be activated independently of p53-for example, during terminal differentiation. Loss of topological control of p21(WAF1) expression is an early feature of malignancy in the colorectal system. Similar to the colonic mucosa, sebaceous glands contain cells that are constantly going through a process of cell division, differentiation, and cell death. This study investigated the expression of p53, p21(WAF1), and the proliferation marker Ki67 in normal sebaceous glands, sebaceous adenoma, sebaceoma, and sebaceous carcinoma.

METHODS

Serial sections were stained with monoclonal antibodies to p21(WAF1), p53, and Ki67 (MIB1) using standard immunohistochemical techniques.

RESULTS

In normal sebaceous glands, p21(WAF1) positive cells were only seen within the differentiating compartment, which was spatially distinct from the cycling peripheral Ki67 positive cells. In sebaceous adenoma and sebaceoma, topological control was maintained, with the distribution of markers being similar to that seen in normal sebaceous glands. Loss of topological control of markers of cellular control was seen in sebaceous carcinoma only. This contrasts with colonic tumours, in which loss of p21 compartmentalisation is seen in adenomas at an early stage of tumour progression.

CONCLUSION

This work confirms the hypothesis that the dysregulation of cell cycle progression is an important process in the development of malignancy within sebaceous glands, although loss of topological control was seen only in sebaceous carcinoma.

Trilateral retinoblastoma variant indicative of the relevance of the retinoblastoma tumor-suppressor pathway to medulloblastomas in humans

Results of recent studies have led investigators to suggest that the retinoblastoma tumor-suppressor (rb) gene plays an underappreciated role in the genesis of brain tumors. Such tumors cause significant rates of mortality in children suffering from hereditary retinoblastoma. It has been assumed that the pineal gland, which is ontogenetically related to the retina, accounts for the intracranial origin of these trilateral neoplasms. To address this issue, the authors describe an unusual trilateral retinoblastoma variant. The authors provide a detailed clinicopathological correlation by describing the case of a child with bilateral retinoblastoma who died of a medulloblastoma. The intraocular and intracranial neoplasms were characterized by performing detailed imaging, histopathological, and postmortem studies. Karyotype analysis and fluorescence in situ hybridization were used to define the chromosomal defect carried by the patient and members of her family. An insertion of the q12.3q21.3 segment of chromosome 13 into chromosome 18 at band q23 was identified in members of the patient's family. This translocation was unbalanced in the proband. The intraocular and cerebellar neoplasms were found to be separate primary neoplasms. Furthermore, the pineal gland was normal and the cerebellar neoplasm arose within the vermis as a medulloblastoma. Finally, the two neoplasms had different and characteristically identifiable cytolological and immunohistochemical profiles. The findings of the present study, taken together with those of recent molecular and transgenic studies, support the emerging concept that rb inactivation is not restricted to central nervous system regions of photoreceptor lineage and that inactivation of this tumor suppressor pathway may be relevant to the determination of etiological factors leading to medulloblastoma in humans.

Chronological ageing and photoageing of the human sebaceous gland

The human sebaceous gland undergoes both extrinsic and intrinsic ageing. The latter is associated with morphological changes and alteration in the sebaceous gland activity. The high androgen-dependent sebum secretion in neonates falls during childhood, starts to rise again during puberty and reaches its maximum in young adults. While the number of sebaceous glands remains the same during life, sebum levels tend to decrease after menopause in females, whereas no major changes appear until the eighth decade of life in men. Reduced androgen levels in aged individuals lead to a slow cellular turnover in the sebaceous glands resulting in hyperplasia of the facial sebaceous glands in advanced age. Ultraviolet radiation and immune suppression (cyclosporin A with corticosteroids) represent cofactors for the development of sebaceous gland hyperplasia. Current molecular findings indicate that overexpression of the ageing-associated gene Smad7 and parathormone-related protein correlate with sebaceous gland hyperplasia, whereas c-myc overexpression is associated with enhanced sebum production. On the other hand, down-regulation of the mismatch repair genes hMLH-1 and hMSH-2 may promote the development of sebaceous gland carcinoma. In addition to spontaneous single tumours, sebaceous gland carcinomas have been reported in immune-suppressed transplant recipients (azathiorpine, cisplatin, cyclosporin A) and in association with the Muir-Torre syndrome. Microsatellite instability with a loss of the mismatch repair gene hMSH-2 has been detected in immune suppressed patients and under photo-induced DNA damage. Topical and systemic oestrogens offer treatment options for skin xerosis in menopausal females. A combination of isotretinoin and interferon-alpha may prevent tumour development in patients with Muir-Torre syndrome.

Sebaceous cell carcinoma of the eyelid and the human immunodeficiency virus

PURPOSE

Patients infected with the human immunodeficiency virus (HIV) are at increased risk for developing malignancies, which are acquired at a younger age and are more aggressive. Sebaceous cell carcinoma is a rare eyelid tumor typically occurring in the seventh decade of life. We report two cases of sebaceous cell carcinoma in young HIV-infected patients.

METHODS

Case series and review of the literature. We describe two HIV-infected patients with sebaceous cell carcinoma of the eyelid and caruncle. The first patient was a 36-year-old woman with a 9-month history of an enlarging right lower eyelid mass. The second patient was a 34-year-old man with a 6-month history of an enlarging right caruncular mass.

RESULTS

Biopsy showed both masses to be sebaceous cell carcinoma. The first patient underwent Mohs' micrographic excision of the lesion followed by reconstruction of the full-thickness eyelid defect with a combination of tarsoconjunctival and myocutaneous advancement flaps. The second patient underwent exenteration because of orbital involvement.

CONCLUSION

Sebaceous cell carcinoma should be considered for any suspicious eyelid lesion in young HIV-infected patients.