Lymphomatoid Papulosis: Clinically benign, histologically malignant, recurrent cutaneous T-cell lymphoproliferative disorder characterized by an infiltration of large atypical cells surrounded by inflammatory cells. The atypical cells resemble REED-STERNBERG CELLS of HODGKIN DISEASE or the malignant cells of CUTANEOUS T-CELL LYMPHOMA. In some cases, lymphomatoid papulosis progresses to lymphomatous conditions including MYCOSIS FUNGOIDES; HODGKIN DISEASE; CUTANEOUS T-CELL LYMPHOMA; or ANAPLASTIC LARGE-CELL LYMPHOMA.Malignant Atrophic Papulosis: Variously described as a vasculopathy, endovasculitis, or occlusive arteriopathy, this condition occurs in a benign cutaneous form and a lethal multiorgan systemic variant. It is characterized by a narrowing and occlusion of the lumen of small to medium-sized blood vessels, leading to ischemia and infarction in the involved organ systems. The etiology and pathophysiology are unknown.Antigens, CD30: A member of the tumor necrosis factor receptor superfamily that may play a role in the regulation of NF-KAPPA B and APOPTOSIS. They are found on activated T-LYMPHOCYTES; B-LYMPHOCYTES; NEUTROPHILS; EOSINOPHILS; MAST CELLS and NK CELLS. Overexpression of CD30 antigen in hematopoietic malignancies make the antigen clinically useful as a biological tumor marker. Signaling of the receptor occurs through its association with TNF RECEPTOR-ASSOCIATED FACTORS.Lymphoma, T-Cell, Cutaneous: A group of lymphomas exhibiting clonal expansion of malignant T-lymphocytes arrested at varying stages of differentiation as well as malignant infiltration of the skin. MYCOSIS FUNGOIDES; SEZARY SYNDROME; LYMPHOMATOID PAPULOSIS; and PRIMARY CUTANEOUS ANAPLASTIC LARGE CELL LYMPHOMA are the best characterized of these disorders.Mycosis Fungoides: A chronic, malignant T-cell lymphoma of the skin. In the late stages, the LYMPH NODES and viscera are affected.Lymphoma, Large-Cell, Anaplastic: A systemic, large-cell, non-Hodgkin, malignant lymphoma characterized by cells with pleomorphic appearance and expressing the CD30 ANTIGEN. These so-called "hallmark" cells have lobulated and indented nuclei. This lymphoma is often mistaken for metastatic carcinoma and MALIGNANT HISTIOCYTOSIS.Skin Diseases, Papulosquamous: A group of dermatoses with distinct morphologic features. The primary lesion is most commonly a papule, usually erythematous, with a variable degree of scaling on the surface. Plaques form through the coalescing of primary lesions.Lymphoma, Primary Cutaneous Anaplastic Large Cell: Anaplastic lymphoma of the skin which develops as a primary neoplasm expressing the CD30 ANTIGEN. It is characterized by solitary nodules or ulcerated tumors.Ultraviolet Therapy: The use of ultraviolet electromagnetic radiation in the treatment of disease, usually of the skin. This is the part of the sun's spectrum that causes sunburn and tanning. Ultraviolet A, used in PUVA, is closer to visible light and less damaging than Ultraviolet B, which is ionizing.Pityriasis: A name originally applied to a group of skin diseases characterized by the formation of fine, branny scales, but now used only with a modifier. (Dorland, 27th ed)Skin DiseasesLymphoproliferative Disorders: Disorders characterized by proliferation of lymphoid tissue, general or unspecified.Skin Neoplasms: Tumors or cancer of the SKIN.Dermatologic Agents: Drugs used to treat or prevent skin disorders or for the routine care of skin.Bowen's Disease: A persistent progressive non-elevated red scaly or crusted plaque which is due to an intradermal carcinoma and is potentially malignant. Atypical squamous cells proliferate through the whole thickness of the epidermis. The lesions may occur anywhere on the skin surface or on mucosal surfaces. The cause most frequently found is trivalent arsenic compounds. Freezing, cauterization or diathermy coagulation is often effective. (From Rook et al., Textbook of Dermatology, 4th ed, pp2428-9)Hodgkin Disease: A malignant disease characterized by progressive enlargement of the lymph nodes, spleen, and general lymphoid tissue. In the classical variant, giant usually multinucleate Hodgkin's and REED-STERNBERG CELLS are present; in the nodular lymphocyte predominant variant, lymphocytic and histiocytic cells are seen.Gene Rearrangement: The ordered rearrangement of gene regions by DNA recombination such as that which occurs normally during development.Copyright: It is a form of protection provided by law. In the United States this protection is granted to authors of original works of authorship, including literary, dramatic, musical, artistic, and certain other intellectual works. This protection is available to both published and unpublished works. (from Circular of the United States Copyright Office, 6/30/2008)Pyoderma: Any purulent skin disease (Dorland, 27th ed).Periodicals as Topic: A publication issued at stated, more or less regular, intervals.Ophthalmology: A surgical specialty concerned with the structure and function of the eye and the medical and surgical treatment of its defects and diseases.Publishing: "The business or profession of the commercial production and issuance of literature" (Webster's 3d). It includes the publisher, publication processes, editing and editors. Production may be by conventional printing methods or by electronic publishing.Pregnancy Tests: Tests to determine whether or not an individual is pregnant.Pregnancy Tests, Immunologic: Methods of detecting pregnancy by examining the levels of human chorionic gonadotropin (HCG) in plasma or urine.Contraception: Prevention of CONCEPTION by blocking fertility temporarily, or permanently (STERILIZATION, REPRODUCTIVE). Common means of reversible contraception include NATURAL FAMILY PLANNING METHODS; CONTRACEPTIVE AGENTS; or CONTRACEPTIVE DEVICES.Pityriasis Lichenoides: A subgroup of PARAPSORIASIS itself divided into acute and chronic forms. The acute form is characterized by the abrupt onset of a generalized, reddish-brown, maculopapular eruption. Lesions may be vesicular, hemorrhagic, crusted, or necrotic. Histologically the disease is characterized by epidermal necrolysis. The chronic form shows milder skin changes with necrosis.Parapsoriasis: The term applied to a group of relatively uncommon inflammatory, maculopapular, scaly eruptions of unknown etiology and resistant to conventional treatment. Eruptions are both psoriatic and lichenoid in appearance, but the diseases are distinct from psoriasis, lichen planus, or other recognized dermatoses. Proposed nomenclature divides parapsoriasis into two distinct subgroups, PITYRIASIS LICHENOIDES and parapsoriasis en plaques (small- and large-plaque parapsoriasis).Pityriasis Rosea: A mild exanthematous inflammation of unknown etiology. It is characterized by the presence of salmon-colored maculopapular lesions. The most striking feature is the arrangement of the lesions such that the long axis is parallel to the lines of cleavage. The eruptions are usually generalized, affecting chiefly the trunk, and the course is often self-limiting.Pityriasis Rubra Pilaris: A chronic skin disease characterized by small follicular papules, disseminated reddish-brown scaly patches, and often, palmoplantar hyperkeratosis. The papules are about the size of a pin and topped by a horny plug.Software: Sequential operating programs and data which instruct the functioning of a digital computer.Skin: The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.Licensure: The legal authority or formal permission from authorities to carry on certain activities which by law or regulation require such permission. It may be applied to licensure of institutions as well as individuals.Moral Obligations: Duties that are based in ETHICS, rather than in law.Congresses as Topic: Conferences, conventions or formal meetings usually attended by delegates representing a special field of interest.Lymphoma, T-Cell: A group of heterogeneous lymphoid tumors representing malignant transformations of T-lymphocytes.Sezary Syndrome: A form of cutaneous T-cell lymphoma manifested by generalized exfoliative ERYTHRODERMA; PRURITUS; peripheral lymphadenopathy, and abnormal hyperchromatic mononuclear (cerebriform) cells in the skin, LYMPH NODES, and peripheral blood (Sezary cells).Lymphoma: A general term for various neoplastic diseases of the lymphoid tissue.Antineoplastic Agents: Substances that inhibit or prevent the proliferation of NEOPLASMS.Dermatitis, Exfoliative: The widespread involvement of the skin by a scaly, erythematous dermatitis occurring either as a secondary or reactive process to an underlying cutaneous disorder (e.g., atopic dermatitis, psoriasis, etc.), or as a primary or idiopathic disease. It is often associated with the loss of hair and nails, hyperkeratosis of the palms and soles, and pruritus. (From Dorland, 27th ed)Spider Bites: The effects, both local and systemic, caused by the bites of SPIDERS.Brown Recluse Spider: A spider of the genus Loxosceles, found in the midwestern and other parts of the United States, which carries a hemolytic venom that produces local necrosis or ulceration.Spiders: Arthropods of the class ARACHNIDA, order Araneae. Except for mites and ticks, spiders constitute the largest order of arachnids, with approximately 37,000 species having been described. The majority of spiders are harmless, although some species can be regarded as moderately harmful since their bites can lead to quite severe local symptoms. (From Barnes, Invertebrate Zoology, 5th ed, p508; Smith, Insects and Other Arthropods of Medical Importance, 1973, pp424-430)Spider Venoms: Venoms of arthropods of the order Araneida of the ARACHNIDA. The venoms usually contain several protein fractions, including ENZYMES, hemolytic, neurolytic, and other TOXINS, BIOLOGICAL.Osteolysis, Essential: Syndromes of bone destruction where the cause is not obvious such as neoplasia, infection, or trauma. The destruction follows various patterns: massive (Gorham disease), multicentric (HAJDU-CHENEY SYNDROME), or carpal/tarsal.NebraskaKansasLymphoma, T-Cell, Peripheral: A group of malignant lymphomas thought to derive from peripheral T-lymphocytes in lymph nodes and other nonlymphoid sites. They include a broad spectrum of lymphocyte morphology, but in all instances express T-cell markers admixed with epithelioid histiocytes, plasma cells, and eosinophils. Although markedly similar to large-cell immunoblastic lymphoma (LYMPHOMA, LARGE-CELL, IMMUNOBLASTIC), this group's unique features warrant separate treatment.Lymphoma, Large B-Cell, Diffuse: Malignant lymphoma composed of large B lymphoid cells whose nuclear size can exceed normal macrophage nuclei, or more than twice the size of a normal lymphocyte. The pattern is predominantly diffuse. Most of these lymphomas represent the malignant counterpart of B-lymphocytes at midstage in the process of differentiation.Prognosis: A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.Immunophenotyping: Process of classifying cells of the immune system based on structural and functional differences. The process is commonly used to analyze and sort T-lymphocytes into subsets based on CD antigens by the technique of flow cytometry.Receptor Protein-Tyrosine Kinases: A class of cellular receptors that have an intrinsic PROTEIN-TYROSINE KINASE activity.