Selected Heritable Skin Diseases of Domesticated Animals
John P. Sundberg in Handbook of Mouse Mutations with Skin and Hair Abnormalities, 2020
Morphologic features — Histologically, systemic histiocytosis is characterized by the presence of perivascular to nodular infiltrates in the dermis and subcutaneous fat, composed primarily of histiocytic cells with various degrees of small lymphocytes, neutrophils, and eosinophils (Figure 11A). Occasionally, there is evidence of both large and small vessel vasculitis as defined by the presence of histiocytic infiltrates into the vessel wall with concurrent thrombosis and vascular necrosis (Figure 11B). The histiocytic cells are relatively monomorphic with moderately abundant, amphophilic cytoplasms with single, round-to-ovoid-to-reniform nuclei having a reticulated chromatin pattern and nucleoli which are often obscured by the chromatin pattern. Mitotic activity is generally low, and abnormal mitotic figures are seldom noted.
Dermatological manifestations of malignancies and dermatological emergencies due to malignancy
Biju Vasudevan, Rajesh Verma in Dermatological Emergencies, 2019
This has been reported with NK/T-cell lymphomas, SPTCL, ALCL, ALL, Hodgkin lymphoma, multiple myeloma, etc. The pathomechanism in malignancy-associated HLH may be the impairment of the cytotoxic pathway by the neoplasm through neoplastic changes in the cytotoxic cell itself or through malignancy-associated immune dysregulation. The strong association with NK/T-cell lymphomas and other EBV-related malignant neoplasms points to a possible common mechanism shared by cases of nonmalignant EBV-associated HLH. HLH is a medical emergency, whether in children or adults, and presents as a purpuric morbilliform rash or erythroderma and unexplained sudden onset of a systemic inflammatory response syndrome (SIRS), including fever, malaise, hepatosplenomegaly, jaundice, generalized lymphadenopathy, and cytopenias. The diagnostic criteria include fever; splenomegaly; cytopenias affecting at least two of three lineages in the peripheral blood; hyperferritinemia greater than 10,000 μg/L; hypertriglyceridemia and/or hypofibrinogenemia; hemophagocytosis in the bone marrow, spleen, or lymph nodes; low or absent NK-cell activity determined by the 51-Cr release assay; and high levels of soluble CD25. The therapy of HLH aims to suppress the exaggerated immune response through the use of immunosuppressive agents. The 2004 treatment protocol formulated at the second international meeting of the Histiocyte Society recommends an 8-week induction therapy with corticosteroids, etoposide, and cyclosporine A as the backbone of HLH treatment plus urgent treatment of the underlying malignancy.
Differential diagnoses of psoriasis
M. Alan Menter, Caitriona Ryan in Psoriasis, 2017
Two major pathologic findings are seen in lichen planus: basal epidermal keratinocyte damage and lichenoid-interface lymphocytic reaction.16,18 The epidermal changes include hyperkeratosis, wedge-shaped areas of hypergranulosis, and elongation of rete ridges that resemble a sawtooth pattern.16,18 Multiple apoptotic cells or colloid-hyaline (Civatte) bodies are seen at the dermal–epidermal junction.16,18 Eosinophilic colloid bodies are present in the papillary dermis. A band-like lymphocytic infiltrate is seen in the papillary dermis that abuts the epidermis.16,18 Many histiocytes and few plasma cells are seen. Separation of the epidermis in small clefts (Max Joseph cleft formation) is occasionally seen.18
Chediak Higashi Syndrome with Hemophagocytic Lymphohistiocytosis
Published in Fetal and Pediatric Pathology, 2023
Moeinadin Safavi, Nima Parvaneh
HLH is characterized by the proliferation of activated lymphocytes and histiocytes with hematophagocytosis. HLH can be primary (due to hereditary diseases like familial hemophagocytic lymphohistiocytosis (FHL), and CHS) or secondary to an underlying infection, autoimmune process, or malignancy. Its clinical manifestations may mimic a systemic infection, hepatitis, or encephalitis. The most prevalent clinical signs are fever and hepatomegaly (90%), splenomegaly (80%), neurological symptoms (45%), and lymphadenopathy (40%). Five out of the eight following criteria are necessary for HLH diagnosis: fever, splenomegaly, cytopenia (≥2 lineages), hypertriglyceridemia and/or hypofibrinogenemia, hemophagocytosis, impaired NK cell function, hyperferritinemia (> 500 ng/mL), and sCD25 > 2400 U/mL [2–5].
Ocular Involvement in the Histiocytoses: A Literature Review with an Illustrative Case Series
Published in Ocular Immunology and Inflammation, 2021
Jennifer Kim, Laura R Steeples, Nicholas P Jones
Histiocytosis is a generic term describing a constellation of cytoproliferative disorders characterised by excessive accumulation of histiocytes (cells of the monocyte/macrophage lineage or Langerhans-type dendritic cells). This results in inflammatory tissue damage which varies from localised and mild to widespread and severe; some cases develop frank malignancy. Many conditions have been individually described with a wide range of clinical presentations, manifestations, and histological phenotypes. In 1987, the Writing Group of the Histiocyte Society1 suggested a classification of three categories: Langerhans cell histiocytosis (LCH) to include disorders where Langherhans-type dendritic cells are prominent; non-Langerhans cell-related histiocytosis (non-LCH) and malignant histiocytoses (MH).
Abdominal wall mycobacterial spindle cell pseudotumor lesion
Published in Baylor University Medical Center Proceedings, 2021
Douglas D. Lim, Abida Bushra, Haiying Zhang
A computed tomography scan of his abdomen revealed a 5.3 cm upper abdominal wall soft tissue mass with erosion of the xyphoid process extending into the omental fat; this was thought to be a neoplasm. A core needle biopsy of the mass revealed large areas of spindled to focally epithelioid cell aggregates with bland nuclei and abundant pale cytoplasm (Figure 1a). Occasional multinucleated histiocytes with lymphocytes, plasma cells, and focal neutrophils were also present. There were no atypical lymphoid cells or evidence of carcinoma. The spindled cells were diffusely positive for CD163 on immunohistochemical staining. S-100 immunostain focally highlighted the spindle cells and intracytoplasmic bacilli. CD34 immunostain was negative in the spindle cells. A Ziehl-Neelsen stain was positive for numerous acid-fast bacilli (Figure 1b). The histologic findings of spindle-shaped histiocytes containing acid-fast bacilli are compatible with the diagnosis of mycobacterial spindle cell pseudotumor.