Organoid nevi and malformations of the skin

5  Non-tumorous skin diseases

5.21  Organoid nevi and malformations of the skin


Tissue nevi and malformations, affecting skin and adnexa. Other malformation (eg. malformaltions of the blood vessels) are mentioned elsewhere.

Clinical signs:


Epidermal nevus papillary lesion with hyperkeratosis, almost without parakeratosis, inflammatory changes are minimal or none.

Inflammatory linear verrucous epidermal nevus (ILVEN) is characterized by psoriatiform acanthosis, focal columnar parakeratosis and inflammation (lymphocytes within the epidermis).

Sebaceous nevus is more complex: papillomatosis, hyperplasia of sebaceous glands (develops at puberty, not prominent in children), malformed sweat glands are often present.

5.21.1  Nevus sebaceus (Jadassohn)

Clinical signs:

  • location: scalp, face
  • alopetic, slightly elevated patch, sometimes linear
  • present at birth, but develops during puberty
  • rarely multifocal, may be large


Nevus sebaceus, upper lip:
Nevus sebaceus, lips, CLINIC (848)


Hyperkeratosis, papillomatosis, dilated follicles, accumulated sebaceous glands (during and after puberty). In addition malformed sweat glands are often present and in about 20% of cases syringocystadenoma papilliferum is found as well. Trichoepithelial induction resembling basalioma is common.

5.21.2  Epidermal nevus

Clinical signs:

  • location: anywhere
  • hyperkeratotic papules solitary and multiple; sometimes is the lesion very large (nevus unius lateris, ichthyosis hystrix)
  • present at birth


Epidermal nevus:
Nevus epidermal, CLINIC (5773)


Prominent hyperkeratosis, papillomatosis, variable acanthosis, sometimes epidermolytic hyperkeratosis (granular degeneration of the epidermis) or dyskeratosis, acantholysis and other changes.


Epidermal verrucous nevus:
Linear epidermal nevus, HE 20x (4479)

Epidermal nevus:
Epidermal nevus, HE 10x (1272)

Epidermal nevus, HE 20x (1273)

Nevus epidermal, HE 40x (1890)

Another case:
Linear epidermal nevus, HE 2.5x (1501)

Linear epidermal nevus, HE 10x (1500)

Another case:
Nevus epidermal, HE 40x (2388)

Another case (newborn with tuberous sclerosis, lesion of the arm):
Nevus epidermal, HE 40x (2350)

Another case, 10 years old boy, forhead:
Nevus epidermal (10 years old boy, forhead), HE 20x (2668)

Another case:
Nevus epidermal, HE 40x (2669)

Linear epidermal nevus with epidermolytic hyperkeratosis (linearly arranged lesion, child):
Linear epidermal nevus, epidermolytic variant, HE 40x (3688)

Another case of epidermal nevus with epidermolytic hyperkeratosis, boy, multiple congenital large linear lesions of the trunk:
Epidermal epidermolytic nevus, HE 40x (6073)

Epidermal nevus of the scalp:
Nevus epidermal, HE 20x (4237)
  [zoomify]  Ichthyosis hystrix (widespread linear epidermal nevus)


Prominent hyperkeratosis, focal epidermolysis, acanthosis, papillomatosis, bacterial and mycotic colonization of almost whole body surface.


Case of ichthyosis hystrix: 2 years old child with very large areas of hyperkeratosis, papillomatosis, desquamation, madidation and chronic bacterial and mycotic colonization of the skin. The lesions were partially present at birth. Chronic sepsis. Autoptic specimen.
Ichthyosis hystrix, HE 20x (566)

Ichthyosis hystrix, Grocott 20x (567)

Ichthyosis hystrix, Grocott 40x (568)

Ichthyosis hystrix:
Ichthyosis hystrix, HE 20x (4713)

Ichthyosis hystrix:
Ichthyosis hystrix, HE 20x (4714)

5.21.3  Inflammatory linear verrucous epidermal nevus (ILVEN)

Clinical signs:

  • erythematous verrucous papules, arranged linearly
  • pruritus
  • location: lower extremities, sometimes elsewhere; usually unilateral


Hyperkeratosis, parakeratosis (parakeratotic areas alternate with orthokeratotic); psoriatiform acanthosis; papillomatosis; often slight spongiosis and lymphocytic exocytosis.

5.21.4  Nevus comedonicus

Clinical signs:

  • papules and comedones, usually linearly arranged
  • lesions are usually isolated, rarely multiple
  • age: from birth to middle age


Comedones filled with keratin; sometimes combined with other organoid nevi; no dyskeratosis. Sometimes combined with inflammation.

5.21.5  Familial dyskeratotic comedones

Clinical signs:

  • rare disease, autosomal dominant inheritance
  • comedones appear during the childhood and adolescence
  • affects the trunk and extremities


Resembles nevus comedonicus, but dyskeratosis and sometimes acantholysis can be found within the walls of the comedones.

5.21.6  White sponge nevus of oral mucosa

Clinical signs:

  • location: oral mucosa (and sometimes rectum, vagina, nasal mucosa, oesophagus
  • age: from birth (and sometimes during the childhood)
  • thickened, white patches of oral mucosa


Acanthotic hyperplasia of oral mucosa, focal intracellular edema of keratinocytes, parakeratosis.

5.21.7  Nevus lipomatosus

Clinical signs:

  • papules and nodules in groups, sometimes yellowish
  • wrinkled surface, soft
  • location: buttocks, hip, often unilateral and linearly arranged
  • age: present at birth or appears during infancy


Groups of mature, normal fat cells within the dermis, varying amount.


Nevus lipomatosus:
Nevus lipomatosus, HE 1.25x (1504)

Nevus lipomatosus, HE 10x (1503)

Nevus lipomatosus:
Nevus lipomatosus, HE 40x (10240)

Another case:
Nevus lipomatosus, HE 20x (2117)

Superficial nevus lipomatosus:
Nevus lipomatosus, superficial, HE 20x (2116)

Nevus lipomatosus with missing sweat glands:
Nevus lipomatosus, HE 20x (14016)

5.21.8  Nevus collagenicus


Focus of thickenned dermis with increased collagen and variable presence of elastic fibres. No or very slight inflammation.

5.21.9  Fibrous hamartoma of infancy

Clinical signs:

  • lesions are present at birth
  • more common in males
  • size: several centimeters
  • location: variable, trunk (esp. axilla) are most common
  • behavior: benign (resection)


Mixture of bundles of spindle cells, fat and pale myxoid areas forming organoid structures.


Fibrous hamartoma of infancy:
Fibrous hamartoma of children, HE 20x (4182)

5.21.10  Aplasia cutis congenita

Clinical signs:

  • congenital defect of the skin
  • distribution: localized or widespread
  • location: variable, the localized form is often localized on the scalp
  • focus of thinned epidermis, alopecia, scarring
  • the defect may be superficial, deep within the dermis or even affect the skull
  • sometimes combined with various congenital anomalies
  • for detailed classification see specialized literature


Epidermal defect, no hair follicles. The surface may be covered by very thin epithelial layer. Later scarring.


Aplasia cutis congenita, 31 — week stillborn infant; trisomy 13 (Patau), macroscopic and microscopic picture:
Aplasia cutis congenita, Macro, autopsy (6037)

Aplasia cutis congenita, HE 40x (6032)

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