Resolving Quandaries in Dermatology, Pathology & Dermatopathology

Cytophagic Panniculitis?

…niculitis can be a feature of malignant histiocytosis, but the histiocytes have the cytological features of neoplastic cells, in contrast to cytophagic histiocytic panniculitis where the cells have the morphological features of mature histiocytes, of…

Histologic Diagnosis of Inflammatory Skin Diseases

Rheumatoid nodule

…hils scattered in the mass of fibrin Fibrin surrounded by thin histiocytes aligned in a palisade Fibrosis, sometimes extensive, in the region beyond the histiocytes and in between palisaded granulomas Late Findings like those described in a lesion…

Histologic Diagnosis of Inflammatory Skin Diseases

Dermatofibroma

…tion of small blood vessels in the region of the infiltrate of histiocytes Histiocytes at the periphery of the nodule “splayed” between thickened bundles of collagen Lymphocytes sometimes present around venules at the periphery of the les…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

…4.1A: Diffuse dermatitis, granulomatous + 10.114.1B: Foamy histiocytes, many of them multinucleate = Xanthogranuloma, fully developed  Lymphocytes, plasma cells, and eosinophils are scattered among the predominant histiocytes, many of which are o…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

…ermis. = Crohn’s disease In addition to the preponderant histiocytes, lymphocytes, plasma cells, and eosinophils are present in the infiltrate. 10.15.3A: Nodular dermatitis, granulomatous + 10.15.3B: Histiocytes in company with degene…

Histologic Diagnosis of Inflammatory Skin Diseases

Errors and Reasons

…ycosis fungoides. Error: Ground-glass cytoplasm is specific to histiocytes of reticulohistiocytic granuloma. Reason: Not only does the cytoplasm of those histiocytes bear no resemblance to ground glass (which is appreciated better by palpation than b…

Histologic Diagnosis of Inflammatory Skin Diseases

Foreign body reaction

…sence of individual cornified cells (squames) in multinucleate histiocytes and of hair shafts either in a zone of suppuration or fibrosis, or surrounded by histiocytes. Splinters display a “stepladder” pattern typical of cellulose. Su…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

…y septal + 10.33.1B: Neutrophils among tiny collections of histiocytes and clefts within those collections = Erythema nodosum These findings represent an early stage in the evolution of erythema nodosum. Collections of histiocytes within which ne…

Differential Diagnosis in Dermatopathology

Differential Diagnosis

…throughout the reticular dermis 2. Infiltrate of epithelioid histiocytes tends to be in discrete loci in the reticular dermis 2. Infiltrate of epithelioid histiocytes tends to be diffuse 3. No band-like character to the infiltrate anywhere in the…