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Abstract

Metatypical basal cell carcinoma: a clinicopathological study

Summary

Introduction: metatypical basal cell carcinoma is an uncommon tumor with particular behavior and
histology. In recent years, an attempt has been made to define the histological criteria, however, there is
currently no consensus on their definition and histopathological characteristics. Objective: to establish
the clinical, epidemiological and histopathological characteristics of metatypical basal cell carcinoma.
Methods: observational, cross-sectional, mixed, descriptive and analytical study, consisting of data
obtained from biopsy reports collecting epidemiological and clinical data, and review of the histological
slides of all cases reported as M-BCC registered from January 2007 to December 2017 in the
dermatopathology laboratory from the dermatology department of the University Hospital of Caracas.
Results: 77 biopsies with a diagnosis of CBC-M were evaluated. The male gender predominated. The
mean age was 64 years ± 1.8 years. The most frequent phototype was III and IV. The evolution of the
tumor had a mean of 2 years. In both men and women, the most frequent location was the face,
especially the nose. Clinical and histologic ulceration was present in 75.3%. The most frequent clinical
presentation was a pearly plaque. The predominant histopathological characteristics were infiltrative
growth pattern, extension to the reticular dermis, presence of 2 zones (transition and basaloid) in 67.5%,
perineural infiltration (IPN) in 7.7%. There was no relationship between tumor depth and the presence of
IPN. Conclusions: this study shows specific histopathological characteristic of the basaloid, transitional
and squamous area that make up the M-BCC not previously described in the literature.

Keywords: metatypical carcinoma; basosquamous carcinoma; basal cell carcinoma;
histologicalvariants; transitionzone.