Conclusion:
LS accounts for 3-5% of all colorectal cancers. Two different variants of LS have been discovered, MTS and TS. In this paper, we focus more on MTS, which is characterized by diagnosis of at least one sebaceous (adenoma, carcinoma, and epithelioma) or keratoacanthomas skin neoplasms and at least one visceral malignancy. The tumors can precede, coincide, or follow the visceral malignancy. In our proband, it followed her visceral malignancy. She also displays autosomal dominant inheritance likely inherited from her maternal grandmother. Genes commonly mutated in MTS include MLH1, MSH2, MSH6, and PMS2, the same gene mutations seen in Lynch Syndrome. MTS is seen in 9.2% of patients with Lynch Syndrome [5]. Treatment for MTS consists of surgical excision or Mohs micrographic surgery for the skin lesions. Oral isotretinoin alone or with interferon-alpha has been shown to suppress new development of sebaceous neoplasms in MTS [6]. Annual skin checks are recommended for continued monitoring for any new skin carcinomas.
Along with managing the skin carcinomas, the various cancers caused by LS must also be managed in these patients. It is recommended that patients with LS undergo annual surveillance colonoscopy from age 25, or 2-5 years from the age of the earliest family member diagnosed before 25 years old [7]. Females diagnosed with LS are recommended to have annual pelvic exam, transvaginal ultrasounds, and in office endometrial biopsy starting at the age of 30-35, it is also recommended that females with LS undergo prophylactic hysterectomy and bilateral salpingo-oophorectomy as a prevention strategy [8]. Annual upper endoscopy with biopsy of gastric antrum is recommended starting also at age 30-35. Treatment of LS is specific to the cancer the patient develops. Treatment can consist of surgery, chemotherapy, and radiation therapy.
In this case, we presented a patient with the Muir-Torre variant of Lynch Syndrome. She originally presented with abdominal pain secondary to left sided metachronous colon cancer. She would then have endometrial cancer. Her history met the Amsterdam II criteria to be screened for LS and her genetic testing revealed mutation of the MSH2 gene. The MSH2 gene accounts for 38% of the gene mutation associated with LS [1]. She also would later be diagnosed with skin cancer (squamous cell and sebaceous), and peritoneal cancer respectively. Her diagnosis of sebaceous carcinoma that presented back in 2008 would further specify her LS diagnosis as MTS. Considering squamous cell carcinoma is her most dominant skin cancer, her case is not the typical presentation of MTS as that is characterized more by sebaceous (adenoma, carcinoma, and epithelioma) or keratoacanthomas skin neoplasm. However, she still meets qualifications required for MTS due to having at least one sebaceous carcinoma along with colon cancer. This patient is currently doing well and continues to receive treatment for her squamous cell carcinoma and IVIG infusions for her immunosuppression. At the age of 67, she demonstrates the high long term survival rate for patients with MTS or LS, as tumors can be monitored with preventative care and are responsive to treatment. Her case also demonstrates the importance of continuous monitoring of all types of cancers in this patient as an atypical cancer for LS can be typical for its variants.