Histologic Diagnosis of Inflammatory Skin Diseases

Images

Images 10.20.1A: Nodular dermatitis, granulomatous + 10.20.1B: Numerous extravasated erythrocytes, siderophages, and fibrocytes = Dermatofibroma An important finding for diagnosis of a dermatofibroma such as this one is seen at the periph…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

…s, neutrophils, and eosinophils in company with fibrocytes and histiocytes, the latter being predominant = Interstitial granulomatous dermatitis with arthritis Some histiocytes have abnormal nuclei and some of them are in mitosis. Histiocytes tend to…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

…dular panniculitis, granulomatous + 10.38.16B: Epithelioid histiocytes, some of them multinucleate, in collections, many histiocytes with vacuolated cytoplasm, and spaces artifactual in the tissue = Silicone granuloma The finely vacuolated cytopl…

Histologic Diagnosis of Inflammatory Skin Diseases

Xanthomas

…yellow color of lesions results from lipid in the cytoplasm of histiocytes and, in the case of eruptive xanthomas, lipid free in the tissue as well. Differential diagnosis histopathologic Lepromatous leprosy sometimes consists of histiocytes that ar…

Histologic Diagnosis of Inflammatory Skin Diseases

Syphilis

…cosis fungoides consists of lymphocytes mostly, rather than of histiocytes and plasma cells. Mucha-Habermann disease is composed almost entirely of lymphocytes, rather than mostly of histiocytes and plasma cells. Psoriasis lacks plasma cells and…

Histologic Diagnosis of Inflammatory Skin Diseases

Leprosy

…action, dense infiltrates of neutrophils are intermingled with histiocytes. Vasculitis of small blood vessels is responsible for ulceration of lesions in states deemed to be reactional. The presence of mononuclear cells, particularly histiocytes, in…

Histologic Diagnosis of Inflammatory Skin Diseases

The Algorithmic Method

…orm dark nucleus and negligible cytoplasm) (Fig. 6.1 A&B); histiocytes are pale (because their nuclei are pale and their abundant cytoplasm is even paler) (Fig. 6.2 A&B); plasma cells are paler than lymphocytes but darker than histiocytes and…

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

Images

…Nodular dermatitis, granulomatous + 10.95.1B: Epithelioid histiocytes aligned in a palisade around foci of degenerated collagen and necrosis of inflammatory cells, the histiocytes in turn being encircled by lymphocytes = Sarcoidosis ¬†Tuberculoid…

Histologic Diagnosis of Inflammatory Skin Diseases

Sarcoidosis

…nfluent Tiny focus of necrosis in the center of collections of histiocytes sometimes Multinucleate histiocytes sometimes present in the granulomas Inclusions, i.e., asteroid bodies (eosinophilic star-shaped bodies) or Schaumann bodies (basophilic lam…