Differential Diagnosis in Dermatopathology

Discussions

…a Spitz’s nevus to become desmoplastic. Parenthetically, fibroplasia in a melanocytic nevus is not limited to Spitz’s nevus. It is seen in Clark’s nevi (“concentric”/”lamellar” fibroplasia), some long-lasting…

Histologic Diagnosis of Inflammatory Skin Diseases

Acroangiodermatitis of Mali/Stewart-Bluefarb syndrome

Acroangiodermatitis of Mali/Stewart-Bluefarb syndrome Presentation stereotypical Age and sex Adults of both sexes Distribution of lesions Localized to the lower part of the legs bilaterally, especially the toes Arrangement of lesions Discrete Indivi…

Histologic Diagnosis of Inflammatory Skin Diseases

Traumatic fat necrosis

…ages present in fat lobules and in the dermis sometimes Slight fibroplasia in conjunction with patchy granulomatous inflammation in fat lobules Late Extensive fibroplasia in patchy distribution in fat lobules Few foam cells residual Correlation cl…

Histologic Diagnosis of Inflammatory Skin Diseases

Identification of Basic Patterns: Subcutaneous Fat: Panniculitis

See Fig. 5.385 A-C. Figure 5.385 Patterns of panniculitis. A. Septal mostly. B. Lobular mostly. C. Septal and lobular “equally.” At scanning magnification, the normal subcutaneous fat is seen to be segregated by struts of fibrous tiss…

Histologic Diagnosis of Inflammatory Skin Diseases

Lymphedema

Lymphedema Presentation stereotypical Age and sex Adults usually, women more than men Distribution of lesions Distal extremities, legs more than arms; genitalia episodically Arrangement of lesions Diffuse involvement of parts, e.g., elephantiasis In…

Histologic Diagnosis of Inflammatory Skin Diseases

Traction alopecia

…of a follicle, rather than along the infundibulum mostly, the fibroplasia around infundibula and follicles is joined by lymphocytes, rather than lymphocytes in a band being separated from those epithelia by a zone of fibroplasia, and fibrous tracks…

Histologic Diagnosis of Inflammatory Skin Diseases

Lichen planus-like keratosis

Lichen planus-like keratosis Presentation stereotypical Age and sex Older individuals bombarded by rays of the sun for many years Distribution of lesions Sun-exposed sites, especially the chest and shoulders Configuration of lesions Round Individual…

Histologic Diagnosis of Inflammatory Skin Diseases

Errors and Reasons

Error: Abortive is an accurate modifier of particular pathologic processes, e.g., abortive dermatofibroma, abortive morphea, and abortive T-cell lymphoma. Reason: The idea itself is abortive! For example, what is called “abortive T-cell lympho…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

Images 10.9.1A: Perivascular and interstitial dermatitis + 10.9.1B: Lymphocytes, plasma cells, and eosinophils = Borreliosis In the United States, the findings pictured here are termed “erythema chronicum migrans”…