Safe ablation of the anal mucosa and perianal skin in rats using Photodynamic Therapy--a promising approach for treating Anal Intraepithelial Neoplasia

BACKGROUND

Anal Intraepithelial Neoplasia (AIN), a pre-cursor of anal squamous carcinoma, is increasingly detected in individuals with impaired immune function. However, choices for effective, low morbidity treatment are limited. Photodynamic Therapy (PDT) is promising as it is known to ablate more proximal gastrointestinal mucosa with safe healing, without damage to underlying muscle. It can also ablate skin with safe healing and minimal scarring.

METHODS

Pharmacokinetics: Normal rats were sensitised with 200mg/kg 5-aminolaevulinic acid (ALA) and killed 1-8h later. Anal tissues were examined by fluorescence microscopy to quantify the concentration of PPIX (protoporphyrin IX, the active derivative of ALA) in anal mucosa and in the underlying sphincter. PDT: Normal rats were sensitised similarly 3h later, laser light (635 nm) was delivered. Anal canal: 50-150 J/cm using 1cm diffuser fibre; for peri-anal skin, 50-200 J/cm(2), using microlens fibre. In each group, 2 rats were killed 3, 7, 14 and 28 days later and the anal region removed for histological examination.

RESULTS

Pharmacokinetics: Peak concentration of PPIX in mucosa was at 3h, peak ratio mucosa: muscle, 6, seen at same time. PDT. Anal canal 50 J/cm: complete mucosal ablation by 3 days, complete regeneration by 28 days. Higher energies caused muscle damage with scarring. Peri-anal skin: 200 J/cm(2); complete ablation of skin, including appendages, complete healing by 28 days. Minimal effect with lower energy.

CONCLUSION

ALA-PDT can ablate anal mucosa and peri-anal skin with safe healing and no underlying damage. However, over treatment can damage the sphincters. This technique is ready to undergo clinical trials.

MR Imaging Findings of Giant Trichilemmal Carcinoma on the Scalp. A Case Report

We describe the magnetic resonance imaging findings of a huge trichilemmal carcinoma (TLC) on the parietal and occipital region of the scalp in one patient. Our aim is to discuss the clinical, radiologic, and pathologic features of scalp TLC and to review relevant literature regarding this tumor. One patient with recent rapid tumor growth in the parietal and occipital region of the scalp underwent MR studies and subtotal resection. The tumor was seen as a poorly marginated and lobulated soft-tissue mass with isointense signal on T1-weighted images and hyperintense signal on T2-weighted images. Necrosis and ulceration were also found on the tumor surface. The TLC has been massively invading the nearby skull, meninges, brain tissue, and superior sagittal sinus. After exhibiting contrast, the tumor showed significant enhancement, with small portions remaining unenhanced. Subtotal excision of the mass and reconstruction of the scalp were performed. Microscopically, the mass was composed of trabecular growth of tumor cells with clear cytoplasm, prominent nucleoli, frequent mitoses, and foci of trichilemmal keratinization. Tumor on the scalp with heterogeneous, mixed signals on T2-weighted images, significant enhancement of solid portion, and local infiltration accompanied by surface deep ulceration may indicate a TLC. Wide surgical excision with tumor-free margins remains the best choice for treatment.

Radiation therapy of recurrent anal squamous cell carcinoma in-situ: a case report

Introduction

High-grade anal intraepithelial neoplasia, also referred to as anal squamous carcinoma in-situ, or Bowen's disease of the anus, make up less than 1% of all digestive system cancers in the United States. The treatment of choice is surgical resection with anal mapping. However, this disease often recurs or persists, requiring additional surgery for these patients. This can compromise the anal sphincter leading to leakage. In this case report, we discuss the efficacy of radiation therapy as a modality to treat post-excisional recurrent Bowen's disease, which may prevent sphincter compromise, leading to improved quality of life.

Case presentation

An 84-year-old Caucasian woman presented with post-excisional persistent/recurrent squamous cell carcinoma in-situ. The initial lesion measured 3 cm in diameter on the right lateral side of the anal margin. A standard surgery consisting of wide local excision with anal mapping was performed. The margins were clear and our patient was followed up. Our patient recurred with a 1.2 × 0.8 cm lesion on the left anal verge extending to the anal canal. A biopsy along with mapping was done, and 2 of the 17 mapping specimens were positive for carcinoma in-situ, one in the anal canal. Due to the location of the positive anal mapping, and in order to prevent sphincter compromise on re-excision, our patient was offered definitive radiation therapy. Two years after radiation therapy, our patient showed no signs of recurrent disease and had good sphincter control.

Conclusion

Although the main treatment modality for treating persistent/recurrent Bowen's disease is surgery, an alternative approach using external beam radiation for CIS may be enough to provide a cure for some patients with recurrent disease.

Anal intraepithelial neoplasia and other neoplastic precursor lesions of the anal canal and perianal region

Anal cancer is rare and this helps to explain why anal pre-neoplastic conditions are poorly understood, especially with regard to their natural history and management. Anal intraepithelial neoplasia is closely linked to human papillomavirus infection and is particularly common in homosexuals and in immunosuppressed patients, especially those with HIV/AIDS. The high regression rates of low-grade anal intraepithelial neoplasia may simply reflect inconsistent pathologic reporting. Higher grades of anal intraepithelial neoplasia may remain static for long periods of time in immunocompetent patients, but those with HIV/AIDS show early and rapid malignant transformation. In general, most anal pre-neoplastic conditions are best diagnosed by biopsy and treated by surgical excision, although local recurrence is a problem. In anal Paget's disease, it is important to ascertain, at the time of diagnosis, whether it is due to a primary in-situ apocrine-type of neoplasia of the anus or if the disease is secondary to an invasive primary carcinoma of the rectum.

Expectant management of anal squamous dysplasia in patients with HIV

PURPOSE

Anal squamous dysplasia is commonly found in patients with HIV infection. There is no satisfactory treatment that eradicates this premalignant lesion with low morbidity and low recurrence. This study reviews a series of patients with HIV and an abnormal anal examination who had squamous dysplasia and who have been followed with physical examination alone and with repeat biopsies as necessary for new or suspicious lesions.

METHODS

We reviewed the charts of 40 HIV-positive men who had squamous dysplasia of the anal canal and anal margin, focusing on history, physical findings, histologic diagnosis, and the occurrence of invasive squamous-cell carcinoma.

RESULTS

Forty HIV-positive men (mean age, 39 years) were followed for anal squamous dysplasia. Biopsies revealed dysplasia, which was usually multifocal. The grade of dysplasia varied, but 28 of 40 patients had at least one area of severe dysplasia. All patients had a follow-up period greater than one year (mean, 32 months; range, 13-130 months). Three patients developed invasive carcinoma while under surveillance, and these were completely excised or cured with chemoradiation.

CONCLUSIONS

Extensive excision for dysplasia in the context of HIV confers high morbidity and questionable benefit, and other treatments are of uncertain value. In a group of patients followed expectantly, most did not develop invasive cancer, and in those who did, early cancers could be identified and cured. Physical examination surveillance for invasive carcinoma may be acceptable for following patients with HIV and biopsy-proven squamous dysplasia.

Radical excision of multifocal anal intraepithelial neoplasia: report of a case

PURPOSE

The aim of this study was to describe the technique of radical excision of multifocal anal intraepithelial neoplasia and discuss controversial issues surrounding the management of this condition.

METHOD

We describe the case of a 31-year-old female with previous vulval warts, vulval squamous carcinoma, and recent immunosuppression who had widespread anal intraepithelial neoplasia excised, and the resulting defect was split-skin grafted, including the anal canal.

RESULTS

Excision and split-skin grafting was successful in removing the disease and left a satisfactory cosmetic and functional result.

CONCLUSION

Diffuse, high-grade, anal intraepithelial neoplasia is rare. Excision of these lesions remains controversial but may be the best option.

Perianal Bowen's disease and anal intraepithelial neoplasia: review of the literature

PURPOSE

The aim of this study was to review the literature with regard to perianal Bowen's disease and anal intraepithelial neoplasia.

METHODS

A literature review was conducted from 1960 to 1999 using MEDLINE.

RESULTS

Perianal Bowen's disease and anal intraepithelial neoplasia are precursors to squamous carcinoma of the anus. They are analogous to and are associated with cervical and vulvar intraepithelial neoplasia, and have human papillomavirus as a common cause. Biopsy and histopathologic examination is required for diagnosis and to distinguish other perianal dermatoses. Treatment options range from aggressive wide local excision of all disease with negative margins to observation alone for microscopic lesions not visible to the naked eye. The disease has a proclivity for recurrence and recalcitrance.

CONCLUSIONS

Most surgeons caring for patients with perianal Bowen's disease and high-grade anal epithelial neoplasia use wide local excision, with an effort to obtain disease-free margins. Some authors have reported the advantages of ablative procedures such as laser ablation and cryotherapy. Microscopic disease found serendipitously in hemorrhoidectomy specimens can probably be treated conservatively with serial examinations alone. There is a lack of controlled data supporting an optimal treatment strategy. A multicenter controlled study comparing wide local excision with ablative procedures may be warranted.