All authors have made significant contributions by making diagnosis and intellectual input in the case and writing the manuscript. Each author has participated sufficiently:

Dariya Chivchibashi, Pavel Pavlov performed the collection and interpretation of data, analyzed histopathology and immunohistochemistry for the diagnosis, drafted the manuscript, wrote the manuscript, gave final approval of the version to be published.

Nikolay Sapundzhiev performed surgical manipulations, collection and interpretation of data, drafted the manuscript, performed the general supervision of the research group, gave final approval of the version to be published.

Maria Tzaneva performed and analyzed histopathology, immunohistochemistry for the diagnosis, drafting the manuscript, performed the general supervision of the research group, gave final approval of the version to be published.