Collagen is the most abundant protein in the body and the main structural component of the skin.
To provide a review of the histopathology of collagen alterations and to propose a classification with the most important types of collagen anomalies in dermatopathology. The authors describe some of the main morphological clues of collagen anomalies for specific diagnosis of some cutaneous inflammatory and neoplastic conditions.
The authors review histopathologic collagen anomalies, concerning both morphology and disposition in some inflammatory and neoplastic cutaneous conditions, and they review previous terminology and proposed a classification of the most important types of collagen anomalies that can be seen in dermatopathological practice.
Collagen anomalies in skin can be classified into lamellar fibrosis, sclerosis, and “balls” and “rings” of collagen. Lamellar fibrosis presents as long and thin collagen bundles forming a delicate network, which can be disposed in a parallel pattern, onion-bulb-like pattern, and storiform pattern. Sclerosis is characterized by large, thick, and eosinophilic bundles of collagen, which may present as a homogenous-diffuse pattern or as individual thick bundles of collagen with few or abundant number of fibroblasts between them. Finally, the authors propose the terms “balls” and “rings” of collagen. The term “balls” of collagen stands for thick, homogenous, eosinophilic, globular collagen bundles, with no distinguishable individual composing fibers, which include the floating sign and the free-floating sign. The term “rings” of collagen is characterized by sclerotic collagen arranged in a homogenous rimming pattern around vessels without independent fibers in its composition.
Collagen anomalies may be important clues to establish specific clues for specific diagnoses in dermatopathology.
*Resident of Department of Dermatology, Department of Dermatology, Hospital Universitario Doctor Peset, Valencia, Spain;
†Resident of Department of Dermatology, Department of Dermatology, Complexo Hospitalario de A Coruña, A Coruña, Spain;
‡Resident of Department of Dermatology, Department of Dermatology, Hospital General Universitario de Ciudad Real, Ciudad Real, Spain;
§Resident of Department of Dermatopathology, Department of Dermatopathology, Hospital General de Mexico Doctor Eduardo Liceaga, Mexico City, Mexico;
¶Resident of Department of Dermatology, Department of Dermatology, Hospital Militar Central de Lima, Lima, Perú;
‖Associate of Department of Pathology, Department of Pathology, Hospital Universtario Virgen de La Macarena, Sevilla, Spain; and
**Associate of Department of Dermatology and
††Chairman of Department of Dermatology, Department of Dermatology, Fundación Jiménez Diaz, Universidad Autónoma, Madrid, Spain.
Reprints: Luis Requena, MD, Department of Dermatology, Fundación Jiménez Díaz, Avenida Reyes Católicos 2, 28040 Madrid, Spain (e-mail: firstname.lastname@example.org).
All authors, faculty, and staff in a position to control the content of this CME activity and their spouses/life partners (if any) have disclosed that they have no financial relationships with, or financial interests in, any commercial organizations pertaining to this educational activity.