Pathology
Images
Atlas of dermatopathology
Josef Feit, Hana Jedličková, Günter Burg, Luděk Matyska, Spasoje Radovanovic et al.
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+ Introduction
+ Literature
+ Support
+ Skin biopsy
+ Non-tumorous skin diseases
+ Skin tumors
+ Cysts of the skin and subcutis
+ Soft tissue lesions
+ Some lesions of the oral cavity
+ Dermatovenerology
+ Collection of histological slides by prof. Günter Burg
+ Collection of histological slides by prof. Werner Kempf
+ Collection of histological slides of dr. Ram Chandra Adhikari
Acanthosis nigricans
Introduction

Several diagnostic units: acanthosis nigricans benigna (pseudoacanthosis) and acanthosis nigricans maligna

Etiology

Benign acanthosis nigricans (intertriginous areas); malignant acanthosis nigricans is a paraneoplastic process.

Clinical signs
  • intertriginous areas
  • papillomatosis
  • hyperkeratosis
  • color: brown
  • the lesions are arranged into crests
  • dull, “velvety” surface
  • differential diagnosis: erythrasma
Pictures

Acanthosis nigricans, axilla, combined with multiple soft fibromas (the patient after thyroidectomy) Acanthosis nigricans, Clinical picture (641)

Acanthosis nigricans, axilla Acanthosis nigricans, Clinical picture (642)

Acanthosis nigricans maligna, widespread perioral and periorbital lesions Acanthosis nigricans, Clinical picture (643)

Acanthosis nigricans Acanthosis nigricans, Clinical picture (2755) Acanthosis nigricans, Clinical picture (2754) Acanthosis nigricans, Clinical picture (2756) Acanthosis nigricans, Clinical picture (2757)

Histology

Fine, low papilomatosis, slight orthokeratotic hyperkeratosis (parakeratosis is minimal or none). Keratinocytes are round, sometimes eosinophilic. In some cases increased pigmentation of the basal layer.