Basal cell carcinoma (BCC)

Basal cell carcinoma (BCC)

Epidemiology:

Basal cell carcinoma (BCC) is recognized as the most prevalent form of skin malignancy, with increasing incidence rates noted globally, particularly in populations with fair skin. Despite the commonality of BCC, spontaneous remission (SR) in this cancer type is infrequent, occurring in approximately 20% of cases, generally when patients exhibit either partial or complete tumor regression without therapeutic intervention ^1,2. The rarity of SR in BCC is accentuated when compared to other malignancies like melanoma and squamous cell carcinoma, which tend to show more robust incidences of spontaneous regression ³.
Clinical Characteristics:

To date, there have been two reported cases of SR involving basal cell carcinoma of the skin. Distinct clinical patterns have been noted among these cases. The patients’ ages at the time of regression ranged from 56 to 84 years, with both occurring in males. See Table 1 below for further information.

Histological Characteristics:

Of the cases analyzed, the tumors were primarily reported as originating from the skin, specifically involving regions such as the right breast and right temporal area. Instances of non-cutaneous malignancies or lesions unrelated to basal cell carcinoma were excluded from this data collection to ensure diagnostic consistency.

Proposed Contributing Mechanisms:

Among the reported cases, the proposed mechanisms of remission were consistent, with both studies attributing the phenomenon to immune-mediated processes. This suggests that activation of the host immune system played a pivotal role in inducing tumor regression. No involvement of hormonal factors, therapeutic interventions, or benign lesion maturation was reported. Collectively, these observations indicate that immune responses are the primary mechanism underlying the spontaneous regression of basal cell carcinoma.

Site and Extent of Remission:

The documented cases demonstrated remission localized to the primary skin lesions. In one case, histologic examination confirmed complete remission within the right breast lesion, while the other exhibited central lesion remission in the right temporal region. Although follow-up information was not reported in either case, these findings suggest that spontaneous remission in basal cell carcinoma may occur at the primary tumor site and reflect localized immune-mediated resolution.

Table 1: Basal cell carcinoma (BCC) SR Cases and Clinical Characteristics

References:

1. Nitzki F., Zibat A., König S., et al. Tumor stroma–derived wnt5a induces differentiation of basal cell carcinoma of ptch-mutant mice via camkii. Cancer Research. 2010;70(7):2739-2748. doi:10.1158/0008-5472.can-09-3743
2. Rieger U., Schlecker C., Pierer G., & Haug M. Spontaneous regression of two giant basal cell carcinomas in a single patient after incomplete excision. Tumori. 2009;95(2):258-263. doi:10.1177/030089160909500223
3. Mitchell R., Kaur A., Kenne F., Khan A., & Zafar W. Spontaneous regression of metastatic lesions of adenocarcinoma of the gastro-esophageal junction. Cureus. 2021. doi:10.7759/cureus.18784
4. Fujimura T, Kakizaki A, Kambayashi Y, Aiba S. Basal cell carcinoma with spontaneous regression: a case report and immunohistochemical study. Case Rep Dermatol. 2012;4(2):125–132. doi:10.1159/000339621
5. Go U, Miyata K, Fujita M, Ohide T, Mitsuishi T. Spontaneous Regression of Annular Basal Cell Carcinoma: A Case Report. Case Rep Dermatol. 2019;11(2):145–149. doi:10.1159/000500711