AK Progressing to High-Risk SCC
An 88-year-old male with a past medical history significant for prostate cancer, hypertension and multiple non-melanoma skin cancers presented for a full-body skin examination in March 2015.
A full-body skin examination was performed at this time and a 6 mm excoriated umbilicated papule was noted on the right preauricular area. The lesion was biopsied and the base was electrodesiccated. The histopathology was consistent with actinic keratosis (AK), inflamed, clear to the base but extending to the lateral margins of the biopsy specimen (Figure 1).
One month later, in April 2015, the patient returned to the office for a follow-up visit. At this time, the biopsy site was healed and there was no evidence of residual AK.
The following month, in May 2015, the patient requested to be seen as he now had developed a nodule in the area of the previous biopsy. The patient was evaluated and was noted to have a 3 cm pink dome-shaped mass with whitish discharge at the site of the prior biopsy. No lymphadenopathy was noted on physical examination.
An additional biopsy was done at this time and was consistent with invasive squamous cell carcinoma (SCC) extending to the deep margin, specifically not keratoacanthoma type. The lesion was surgically excised in June 2015 with 8 mm margins and down to parotid fascia (Figure 2).
Despite excising to parotid fascia, the deep margin remained positive. After discussion with the patient regarding various treatment options, the decision was made to refer the patient to radiation oncology. A computed tomography scan was negative for metastatic disease and the patient underwent radiation therapy. The patient is closely followed by radiation oncology and dermatology with no recurrence noted at this time.
The proximity to and possible invasion of the parotid fascia increases the risk of the SCC to have lymphatic spread and high-risk features. Twenty percent of patients without lymphadenopathy have subclinical metastasis. Mendenhall et al1 stated that postoperative radiotherapy is an ideal modality in a patient situation where there is a high likelihood of residual disease after surgical intervention.
According to Jennings and Schmults,2 high-risk cutaneous SCC is best approached with surgical excision combined with adjuvant radiation therapy if indicated.
High-risk features of SCC according to the American Joint Committee on Cancer include: depth/invasion >1 mm thickness, Clark level >IV or perineural invasion; anatomic location: primary site on the ear or primary site non-hair-bearing lip and differentiation: poorly differentiated or undifferentiated.
Additional factors cited by Jennings and Schmults include diameter >2 cm, infiltrated/desmoplastic growth pattern and history of local recurrence. Cutaneous SCC invading past subcutaneous fat is strongly associated with disease-specific death.2 Multiple guidelines exist to classify high-risk SCCs.
Our patient has 2 high-risk features of SCC including size (>2 cm) and depth of invasion. A recent review3 discussed the implications of these high-risk features including risk of local recurrence and metastasis. Our patient has approximately a 17% rate of local recurrence and a 40% risk of metastasis.
The decision to refer our patient to radiation therapy subsequent to wide local excision was based on age, tumor proximity to the parotid fascia and the understanding of the potential for high-risk SCC to be invasive. The positive margin adjacent to the parotid fascia was especially worrisome as it is a location with extensive neurovascularity and propensity to invade.
A study by Chen et al4 concluded that surgery and adjuvant radiation therapy were associated with improved survival compared to radiation alone and no treatment.
We report this case because it highlights the paramount importance of identifying and aggressively treating high-risk SCC. Clinically suspicious lesions should be closely followed.
Accordingly, if the site recurs or evolves into a new lesion, re-biopsy is warranted. The risk of AK progressing to SCC is unclear but ranges from 0.1% at the lowest spectrum to 20% at the highest. For a patient with multiple AKs, the rate of progression to invasive SCC can be as high as 80%.5
Patients with a high-risk SCC require intervention to reduce the risk of metastasis. In this situation, rapid classification of the SCC by determining high-risk factors along with patient comorbidities will help determine if the patient will need surgical intervention alone, surgery plus radiation or referral to surgical oncology.
In our 88-year-old patient, radiation after wide surgical excision left him with an intact facial nerve and an acceptable outcome thus far. This case emphasizes the importance of histopathologic correlation and prompt identification of high-risk SCC rapidly progressing from an AK.
Dr. Lombardi is a fellow at Affiliated Dermatologists in Morristown, NJ.
Dr. Rogachefsky is a practicing dermatologist and the program director of the ACGME-approved Procedural Dermatology Fellowship at Affiliated Dermatologists & Dermatologist Surgeons in Morristown, NJ.
Disclosure: The authors report no relevant financial relationships.
1. Mendenhall WM, Amdur RJ, Hinerman RW, Cognetta AB, Mendenhall NP. Radiotherapy for cutaneous squamous and basal cell carcinomas of the head and neck. Laringoscope. 2009;119(10):1994-1999.
2. Jennings L, Schmults C. Management of high-risk cutaneous squamous cell carcinoma. J Clin Aesthet Dermatol. 2010;3(4):39-48.
3. Navarette-Dechent C, Veness MJ, Droppelmann N, Uribe P. High-risk cutaneous squamous cell carcinoma and the emerging role of sentinel lymph node biopsy: A literature review. J Am Acad Dermatol. 2015;73(1):127-137.
4. Chen J, Pappas L, Moeller J, et al. Treatment of oropharyngeal squamous cell carcinoma with external beam radiation combined with interstitial brachytherapy. Head Neck. 2007;29(4):362-369.
5. Costa C, Scalvenzi M, Ayala F, Fabbroncini G, Monfrecola G. How to treat actinic keratosis? An update. J Dermatol Case Rep. 2015;30;9(2):29-35.