Skin - Nonmelanocytic tumors
Other tumors of skin
Dermatopathology patterns

Author: Hillary Elwood, M.D., Christopher Hale, M.D. (see Authors page)

Revised: 22 May 2017, last major update June 2012

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: intraepidermal epithelioma of Borst-Jadassohn, cutaneous horn, pseudoepitheliomatous hyperplasia
Cite this page: Dermatopathology patterns. PathologyOutlines.com website. http://pathologyoutlines.com/topic/skintumornonmelanocyticpatterns.html. Accessed May 29th, 2017.
Abscess
See Abscess under Skin-nontumor > Infectious Disorders
Borst-Jadassohn phenomenon
Definition / General:
  • Previously called intraepidermal epithelioma
  • Not clearly defined
  • Likely heterogeneous group of disorders (Am J Dermatopathol 2011;33:492) including irritated seborrheic keratosis, eccrine poroma and other intraepidermal sweat gland tumors
Cutaneous Horn
Definition / General:


Clinical Features:
  • Usually solitary
  • Predilection for the head and neck and hands of older persons
  • Hard yellow to brown skin excrescence composed of compact keratin resembling a horn
  • Can be straight or curved and can measure up to several centimeters in length


Case Reports:


Clinical Images:

Images hosted on other servers:

Cutaneous horn



Micro Description:
  • Usually epidermal type keratin (with granular layer)
  • Occasionally has trichilemmal-like features (no granular layer but deep red granules) - termed trichilemmal horn
  • Examination of the base of the lesion is needed to determine the underlying etiology
  • Sometimes base contains epidermal hyperplasia without atypia


Micro Images:

Images hosted on other servers:

Actinic keratosis with cutaneous horn

Low power

Verruca vulgaris

Exfoliative dermatitis / erythroderma
Clinical features:
  • Total body erythema (> 90% of cutaneous surface) and scaling, due to drug reaction, allergic contact dermatitis, psoriasis, pityriasis rubra pilaris, malignancy
  • Associated with dermatopathic lymphadenitis
  • May clinically resemble chronic graft versus host disease (Ann Dermatol 2009;21:319)


Clinical images:

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Various images



Microscopic (histologic) description:
  • Nonspecific changes
  • May have lichenoid dermatitis


Differential diagnosis:
  • Sezary‚Äôs syndrome / mycosis fungoides (eMedicine)
Pseudoepitheliomatous Hyperplasia
Definition / General:
  • Pseudoepitheliomatous (pseudocarcinomatous) hyperplasia (PEH) is a histologic pattern, not a specific diagnosis
  • Histologic mimic of squamous cell carcinoma
  • PEH occurs in a wide range of settings such as:
    • Chronic irritation, including borders of ulcers and healing wounds, urostomy / colostomy sites, prior biopsy site, stasis ulcer, pyoderma gangrenosum, prurigo nodularis, lichen simplex chronicus, halogenoderma
    • Inflammatory dermatoses such as hypertrophic lichen planus, pemphigus vegetans, chronic arthropod bite
    • Infectious dermatoses such as tuberculosis verrucosa cutis, pyoderma vegetans, atypical mycobacterial infection, deep fungal infection
    • Overlying tumors such as granular cell tumor, cutaneous T cell lymphoma, CD30+ lymphoproliferative disorders, Spitz nevi, melanoma
  • Differential for PEH with intraepidermal neutrophilic microabscesses includes:


Case Reports:


Micro Description:
  • Prominent acanthosis of epidermis and adnexal epithelium with deep, somewhat bulbous, downgrowths of epithelial cells that may appear invasive
  • Dermal fibrosis and reactive vascular proliferation may be present
  • In cases associated with an inflammatory or infectious process, there may be intraepidermal microabscesses
  • Often associated with trapping of elastic fibers within epidermis
  • Absent or minimal atypia, rare mitoses


Micro Images:

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Inflammatory infiltrate in dermis

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Surface epithelium

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Acanthotic squamous epithelium

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Mild chronic inflammation

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Pseudoepitheliomatous hyperplasia



Differential Diagnosis:
  • Pseudoepitheliomatous hyperplasia can be seen in a number of settings, as outlined above, and its presence should prompt a search for an underlying infectious process, inflammatory process or tumor as appropriate
  • Well differentiated squamous cell carcinoma:
    • Can be extremely difficult to impossible to distinguish PEH from squamous cell carcinoma (SCC), especially on superficial shave biopsies
    • PEH is mainly differentiated by clinical findings and / or the discovery of an underlying reason for its presence
    • Findings that favor SCC include increased mitoses particularly atypical mitoses, more pronounced cytologic atypia, perineural / lymphovascular invasion