Background: Exaggerated reaction to insect bites, mainly to mosquitoes, is infrequently described in patients with chronic lymphocytic leukemia. Skin lesions usually appear months to years after the diagnosis of leukemia and are unrelated to laboratory findings, disease course, or therapy.Observations: We describe 8 patients with various hematologic disorders (chronic lymphocytic leukemia, acute lymphoblastic leukemia, acute monocytic leukemia, mantle-cell lymphoma, large-cell lymphoma, and myelofibrosis) who developed insect bite-like reaction. Although the clinical picture and the histological characteristics of the lesions were typical for insect bites, none of the patients actually had a history, course, or response to treatment suggestive of arthropod assaults. In 2 patients, the eruption preceded the diagnosis of the ma-lignant neoplasm. The rash persisted for months to years and was resistant to therapies other than systemic corticosteroids. The 3 patients with chronic lymphocytic leukemia seemed to have a worse prognosis than expected for their disease. In 1, the polymerase chain reaction detected leukemic cells in the infiltrate.Conclusions: Insect bite-like reaction is an infrequent, disturbing, and difficult-to-treat nonspecific phenomenon in patients with hematologic malignant neoplasms. Since it may precede the hematologic disorder, oriented evaluation is warranted. We speculate that immunodeficiency plays a role in its pathogenesis; however, the exact pathogenesis and its prognostic implications await further studies.

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SCC of the hair follicle represents a poorly recognized but distinctive subset of SCC of the skin that should be considered in the differential diagnosis of other cutaneous epithelial tumors. The term follicular SCC (FSCC) is proposed for this neoplasm.

Our cases provide additional evidence supporting the benign nature of this atypical vascular proliferation, not recurring, never developing metastases and being cured readily by local excision. Clinical, histopathological and ultrastructural findings suggest a lymphatic origin. Whether these lesions represent a neoplastic or a reactive condition secondary to radiotherapy is unclear. The name 'benign lymphangiomatous papules of the skin following radiotherapy' is proposed.

Erythema annulare centrifugum is classified generally into a superficial and a deep type. Whether those types are variants of the same process or unrelated to one another, and whether they represent non-specific patterns or specific clinico-pathologic entities, is controversial. To answer those questions, we analyzed 82 biopsy specimens from 73 patients with a clinical and histopathologic diagnosis of erythema annulare centrifugum, gyrate erythema, or figurate erythema regarding a variety of clinical and histopathologic findings. We found substantial differences between cases with a wholly superficial type and cases with a superficial and deep infiltrate. Clinically, a collarette of scales was seen only in the superficial type. Histopathologically, some findings were much more common in the superficial type (eg, spongiosis, parakeratosis, crusts, edema of the papillary dermis, epidermal hyperplasia) and others in the deep type (eg, sleeve-like arrangement of the infiltrate, melanophages, subtle vacuolar changes at the dermo-epidermal junction, individual necrotic keratinocytes). Whereas cases of the superficial type could be distinguished from differential diagnoses by a variety of clinical and histopathologic findings, most cases of the deep type showed subtle signs of lupus erythematosus. Neither type was associated consistently with any other systemic disease. Because the superficial and the deep type of erythema annulare centrifugum seem to be unrelated to one another, they should not be referred to by the same name. We believe that the term should be reserved for the superficial type because the latter seems to be a specific clinico-pathologic entity. By contrast, most cases of the deep type seem to be annular examples of tumid lupus erythematosus and should be diagnosed that way. If findings militate against the diagnosis of lupus erythematosus, we suggest using a descriptive term that signals non-specificity-namely, deep figurate erythema.