INTRODUCTION
Basal cell carcinoma (BCC) is a skin malignancy that commonly affects sun-exposed areas of the body such as the head and neck region (Jeon et al. 2006; Wang et al. 2010). However, BCC of the scrotum quite uncommon (Dai et al. 2012; Jeon et al. 2006; Kinoshita et al. 2005) and its pathogenesis is not well understood (Jeon et al. 2006). It is thought to be more aggressive and metastasizes earlier than BCC of other parts of the body (Kinoshita et al. 2005). Localized scrotal BCC is usually treated with wide local excision (Delto et al. 2016; Jeon et al. 2006; Ribuffo et al. 2002; Wang et al. 2010) but metastatic disease may require systemic chemotherapy for disease control (Cieplinski 1984; Jeon et al. 2006). To our knowledge, scrotal BCC occurring concurrently with another metastatic carcinoma has never been reported. We encountered a rare case of scrotal BCC in the presence of metastatic squamous cell carcinoma (SCC) of the ear canal. This case illustrates the challenges encountered in diagnosing and treatment. It also highlights a palliative strategy that provides the patient with a good quality of life.
CASE REPORT
A 70-year-old male complained of having a chronic and non-healing ulcer on his left hemiscrotum for two yrs. He used to work as a supervisor at a chemical factory for over 20 yrs. The job involved exposure and close contact with various chemicals including magnesium sulphate, nitric oxide, ammonia, paraquat, liquid hydrogen, chlorine gas and sulphur compounds. The scrotal lesion was made known to us while he was undergoing investigation for SCC of his right external auditory meatus. The SCC was found to have metastasized to the liver and lymph nodes in the abdomen and pelvis. The concomitant presence of this metastatic SCC raised the suspicion that the scrotal lesion could be a metastatic secondary. On physical examination, the lesion was located at the inferior part of the scrotum. It measured 3cm x 4cm in size, and had pearly irregular borders and central ulceration (Figure 1). It had a hard consistency but it did not feel adherent to the underlying tunica vaginalis and testes. The clinical appearance of this scrotal lesion was uncharacteristic of SCC. His inguinal lymph nodes were also found to be enlarged bilaterally. A wedge biopsy of the scrotal lesion unexpectedly diagnosed it to be BCC instead of metastatic SCC (Figure 2).
He underwent wide local excision (WLE) of the scrotal lesion with the intention for local disease control. Intraoperatively, the tumour was resected with at least 1 cm macroscopic margin. However, the histopathological examination (HPE) showed nodular, infiltrative pattern BCC of the scrotum with inadequate resection margin. Meanwhile, he developed a new satellite scrotal sinus just near the base of penis. He subsequently underwent further excision of the scrotal scar and sinus. While the scrotal scar HPE showed good clearance margin this time, the scrotal sinus was found to harbour even more BCC. After surgery, he was treated with palliative chemoradiation consisting of 6 cycles of cisplatin 30mg/m2, and 70 Gy in 35 fractions of radiotherapy to the metastatic neck and abdominal lymph nodes. He remained well six month after completing palliative treatment and there was no local recurrence of the scrotal BCC.
DISCUSSION
Basal cell carcinoma is the commonest skin cancer in most parts of the world (Lomas et al. 2012). It is widely accepted that excessive exposure to ultraviolet (UV) radiation is a major risk factor for developing BCC (Wang et al. 2010). Therefore, most BCC occur on parts of the skin that are usually exposed to sun (Jeon et al. 2006), and BCC of the scrotum is understandably quite uncommon (Dai et al. 2012; Jeon et al. 2006; Kinoshita et al. 2005). Unlike SCC of the scrotum that has several established risk factors, scrotal BCC does not have any clear relations with carcinogen exposure. (Jeon et al. 2006). Indeed, its pathogenesis still remains unclear and few postulations were proposed. These include impaired immune surveillance, genetic mutation and even chronic irritation (Jeon et al. 2006; Ouchi & Sugiura 2008; Wang et al. 2010).
Scrotal BCC is also thought to behave more aggressively than its counterpart located elsewhere on the body. Metastatic scrotal BCC is known to occur much earlier, at around 2-3 yrs after the initial diagnosis; in contrast, BCC on other sites that metastasize at an average time of 11 yrs after being diagnosed (Kinoshita et al. 2005). The commonest sites of metastasis are lymph nodes, lungs and bones (Kinoshita et al. 2005). Nevertheless, there was a single case report of scrotal BCC that remained dormant for over 50 yrs (Wang et al. 2010). Unfortunately, we were unable to predict which patient would have metastasis sooner than others. Previous attempts at using histological features to predict metastatic potential have been largely unsuccessful (Kinoshita et al. 2005). Therefore, we must remain vigilant for the possibility of early distant spread in all cases of scrotal BCC.
The present case was a diagnostic challenge to us because while the patient was being investigated for metastatic SCC of the external auditory meatus, he alerted us about an ulcerating lesion on his scrotum. The initial impression was that the scrotal lesion should also be squamous cell in origin and treatment would follow the course for SCC. However, a biopsy of the lesion found it to be BCC. This then posed a question of whether to wide local excision of the scrotal was appropriate in the presence of widespread metastatic SCC from his ear. Furthermore, we also faced a dilemma in deciding the systematic therapy that he should receive in this unusual situation.
Most authors agree that surgery is the mainstay of treatment for localized scrotal BCC (Delto et al. 2016; Jeon et al. 2006; Ribuffo et al. 2002; Wang et al. 2010). A clear surgical margin of > 6 mm reduces the risk of disease relapse (Delto et al. 2016). Other authors advocate greater clear surgical margin of 2-3cm for complete resection of the local disease (Hernández-Aragüés & Baniandrés-Rodríguez 2016). In cases where metastases occurred, systemic chemotherapy should be administered (Cieplinski 1984; Jeon et al. 2006) and a cisplatin-based combination seems to produce acceptable results (Cieplinski 1984). Of particular note, metastatic scrotal SCC can also be treated with cisplatin in combination with methotrexate and bleomycin (Vyas et al. 2014).
We offered the patient wide local excision of his scrotal BCC as a means for local control and also to free him from the constant discomfort of an ulcerating lesion. This was followed by palliative systemic treatment with cisplatin chemotherapy, and radiotherapy to the metastatic lymph nodes at his neck and abdomen. This treatment strategy gave him a good quality of life at 6 months, post-chemoradiation.
CONCLUSION
In conclusion, a patient with scrotal BCC presenting concurrently with metastatic SCC of the ear is rare and can be a challenge to manage. A careful and individualized treatment plan, combining surgery, chemotherapy and radiotherapy can provide excellent palliative outcome in this clinical scenario.