A 101-year-old woman has had an occasionallypruritic and tender growthon her face for about 2 months. Thegrowth has doubled in size over the past2 weeks. She has no personal or familyhistory of cancer or significant dermatologicdisorders.
A 101-year-old woman has had an occasionallypruritic and tender growthon her face for about 2 months. Thegrowth has doubled in size over the past2 weeks. She has no personal or familyhistory of cancer or significant dermatologicdisorders.The patient is well-nourished,alert, and oriented. She has a 2.5-cmviolaceous tumor over the left zygoma(Figure). In addition, there is a palpable4.5-cm subcutaneous nodule. Nopalpable cervical adenopathy is noted.An incisional biopsy is performed.Histopathologic examination revealsdiffuse, invasive Merkel cell carcinomaand actinic keratosis.The patient undergoes Mohs micrographicsurgical excision. An areaof induration inferior and lateral tothe main mass is detected intraoperativelyand excised as well. Histopathologicstaining reveals that the mass isa satellite lesion. The excision site isclosed primarily. Adjuvant radiationtherapy is not necessary at this point,because no palpable lymph nodes arepresent.At a follow-up visit about 10weeks after surgery, the patient reportsno postoperative complications; however,the lesion has recurred. A 3-cm,pink, multilobular nodule with erosionsis noted along the inferior margin ofthe surgical site. She undergoes a Mohssurgical excision, and another satellitelesion is found during the procedure.The surgeon recommends postoperativeradiation therapy.The patient dies about 3 monthsafter the second procedure. Accordingto her son, the death was of naturalcauses and no autopsy was performed.MERKEL CELL CARCINOMA:AN OVERVIEW
This rare carcinoma of neuroendocrinederivation occurs predominantlyin older patients; those who areolder than 65 years are at increasedrisk. 1 The overall incidence is about0.24 per 100,000 persons.1 Typically,the tumor arises on sun-exposedareas, such as the head, neck, andarms, but it has been reported on thetrunk and covered areas as well. Thisrapidly growing neoplasm frequentlyappears as a pink, reddish brown, orbluish red cutaneous and/or subcutaneousnodule of 0.5 cm or larger thatmay have ulcerations. Regional lymphnodal involvement, distant metastasis,and recurrence at the excision siteare common. 1,2Although this carcinoma commonlyoccurs on sun-exposed areas,there is no evidence that sun exposure is a contributing factor. Someexperts have suggested a relationshipbetween Merkel cell carcinoma andsquamous cell carcinoma3-6; othershave reported an association with arsenicexposure.7-9DIAGNOSISConsider basal cell carcinoma,squamous cell carcinoma, melanoma,and adnexal tumors in the differentialdiagnosis. Key clinical features thatdistinguish Merkel cell carcinomafrom other conditions in the differentialinclude:
Theseinclude wide excision, Mohs micrographicexcision, radiation therapy,and chemotherapy. Although no controlledstudies have contributed tothe standardization of therapy, welldocumented,case-based evidencehas shown that tumors recur less frequentlyafter wide excision withmargins of greater than 3 cm thanafter wide excision with narrowermargins.
Adjuvant radiation therapyfollowing excision also has been reportedto decrease recurrence rates.
Radiation therapy has been usedalone, as has chemotherapy, especiallyin patients with large, nonresectabletumors. However, adjuvant radiationtreatment has not been shownto be of benefit in conjunction withMohs micrographic excision.
In Mohs surgery, the area to beexcised is systematically divided intosections that are consecutively removedand histologically analyzed;this allows for mapping of the tumorand identification of its borders. This procedure ensures tumor-free marginsand maximal sparing of healthytissue, which is particularly desirablewhen regions such as the head andneck are involved.
Treatment of this patient.
Mohsmicrographic surgical excision wasselected based on the lesion's sizeand location. Adjuvant radiation therapywas deferred initially because nocervical nodes were palpable; additionalconsiderations were the patient'sage and her inability to travelto receive treatments.The goal of this treatment planwas to delay and/or prevent the disease process and to provide the mostbenefit with minimal risks. Radiationtherapy could have possibly diminishedher quality of life and wouldhave minimally increased survival. Ifno treatment was provided, the tumorwould have continued to rapidly invadeher face, and she would likelyhave died of the cancer.
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