Plates 11-1 through 11-4, pp. 236-243

Chapter 3, Tissue Repair

• "Repair by Connective Tissue" pp. 70-74
• "Cutaneous Wound Healing" pp. 74-77
• "Pathologic Aspects of Repair" pp. 77-78

Chapter 22, The Skin, pp. 837- 857

Skin Pathology Cases

UMich Slide 24 [WebScope][ImageScope]

Skin and Subcutis: Chronic Ulcer

This slide represents a non-healing scalp lesion from a 43-year-old man.

• Note under the scanning power of your microscope that the cutaneous surface is interrupted by a defect which penetrates deep into the tissue. Note, also, under the scanning power that there is a layer of exudate surfacing this defect with an underlying loose tissue and then an outer “shell” of dense fibrous tissue.

• Under the higher powers of your microscope note that the ulcer is lined by loose fibrinopurulent exudate, immediately beneath which is a zone of maturing granulation tissue (with various types of leukocytes), deep to which is a zone of relatively mature scar.

• This lesion is good example of chronic inflammation with evidence of advanced scarring as well as continued exudation. An inspection of the epidermal borders of the lesion will reveal attempted regeneration of the epithelium.

• Were this lesion finally to heal, what would be the sequence of histologic events and what would be the ultimate appearance?
  

UMich Slide 25 [WebScope][ImageScope]

Skin: Scar

This 27-year-old patient had a pigmented skin lesion excised which turned out to be a melanoma. 6 weeks later, another biopsy was performed at the same site to confirm complete removal of the neoplasm and absence of recurrence. As shown in the specimen, there is no remaining neoplasm, but scar tissue from initial biopsy procedure is evident.

• Under the scanning power of your microscope identify the epidermis and, at either end of the specimen some of the dermal appendages. Note that in the central portion of the specimen dermal appendages are absent and a dense connective tissue “replaces” the dermis. This is a scar. Note that the epidermis over the area of scar shows flattening of the normal rete ridge pattern seen towards the ends of the specimen. This is regenerated epidermis over the scar.

• A quick glance at UMich Slide 26 [WebScope][ImageScope] will reveal an abnormal variation on this same theme. This specimen represents a large nodule which developed in a surgical incision. You will note from the shape of the lesion that this was a “knob” projecting from the skin surface, covered with an intact (regenerated ) epidermis. This is a keloid, actually a nodule of overgrown scar tissue. Under the higher power of your scope note the peculiar coarse, glassy collagen which accounts for the bulk of the keloid. What is the significance of such a lesion?

UMich Slide 178 [WebScope] [ImageScope]

History: A 35-year-old man was clearing a path in the woods. When he returned home, he noticed an intensely pruritic linear vesicular eruption on his extensor forearms. A skin biopsy was taken.

Histologic features: There is pronounced spongiosis (intercellular edema) within the epidermis resulting in intraepidermal vesicles. Exocytosis of lymphocytes (lymphocytic spongiosis) may be seen in the epidermis. There is a superficial perivascular lymphocytic infiltrate.

Based on the history, presentation, and histological findings, what do you think is the best diagnosis for this case?

1. What type (I, II, III, or IV) of allergic hypersensitivity reaction is this?

2. Does allergic contact dermatitis occur with someone's first exposure to the antigen?

UMich Slide 198 [WebScope] [ImageScope]

History: A 45-year-old woman complained of a scaly rash present for many years. On exam were multiple, well demarcated erythematous papulosquamous plaques on the elbows, arms and knees. Erythema and white scale were also present on her scalp. A skin biopsy was taken.

Histologic features: There is near confluent parakeratosis, hypogranulosis, and regular psoriasiform hyperplasia of the epidermis with slight clubbing of the rete pegs. Neutrophilic fragments can be identified in the stratum corneum and in the upper epidermis. Dilated and tortuous blood vessels are seen in the dermal papillary tips.

Based on the history, presentation, and histological findings, what do you think is the best diagnosis for this case?

UMich Slide 39 [WebScope] [ImageScope]

History: A 12-year-old boy complained of a slowly growing papule with a thickened surface on his finger. The lesion was biopsied.

Histologic features: There is hyperkeratosis, papillomatosus, and acanthosis. Within the granular cell layer, diagnostic koilocytes containing "raisin-like" nuclei are seen. Intracytoplasmic viral inclusions may also occasionally be seen.

Based on the history, presentation, and histological findings, what do you think is the best diagnosis for this case?

1. What is the cause of this condition?


2. Is it infectious? If so, how is it spread from person to person?


3. Are there any types of these lesions that are associated with an increased risk of cancer?

UMich Slide 128 [WebScope] [ImageScope]

History: A 65-year-old man complained of a slowly growing lesion on his nose. On exam, an ulcerated pearly nodule with dilated blood vessels was noted. The lesion was surgically excised and submitted to pathology for analysis.

Histologic features: There are multiple islands of neoplasia extending into the dermis demonstrating peripheral palisading and stromal retraction artifact. Connection of the neoplastic islands to the stratum basale of the epidermis is often identified.

Based on the history, presentation, and histological findings, what do you think is the best diagnosis for this case?

1. How common is this type of lesion compared to malignancies observed in humans?


2. What environmental factor predisposes to the development of this lesion?


3. In what location on the body does this type of lesion most frequently develop?


4. What is the usual biologic behavior of this type of lesion? What is its metastatic potential?

UMich Slide 123 [WebScope] [ImageScope]

History: A 30-year-old woman presented with a symmetric, uniformly pigmented, dome-shaped papule on her face. She requests its removal.

Histologic features: There is a dome-shaped, symmetric papule with multiple nests of bland nevus cells at the dermo-epidermal junction and in the dermis. Nevus cells are slightly larger in the superficial portion of the lesion and become smaller or "mature" with descent into the dermis. There is no cytologic atypia.

Based on the history, presentation, and histological findings, what do you think is the best diagnosis for this case?

1. What is the cell of origin of this lesion?


2. Can this particular type of lesion serve as a precursor to malignancy?
   
   
3. If this lesion were present from birth, very large, or present in large numbers, would this confer any greater risk of developing a malignancy?

Slide 129 [WebScope] [ImageScope]

History: A 24-year-old medical student, who used to work summers as a lifeguard, complained of a changing mole on her leg. It had begun to itch and recently darkened in color. The lesion was biopsied.

Histologic features: There are cytologically atypical melanocytes at the dermo-epidermal junction and in the dermis. Nuclei are large with occasionally prominent nucleoli. Rare mitotic figures are present. The lesion is asymmetric and poorly circumscribed.

Based on the history, presentation, and histological findings, what do you think is the best diagnosis for this case?

1. What are the risk factors for the development of this type of lesion?


2. What are some of the key factors to consider in the evaluation of this type of lesion?