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Notes: A series of 25 cutaneous B-cell lymphoid proliferations was analyzed for the presence of the (14;18) translocation using the polymerase chain reaction, functional sequences of rearranged chromosomes 14 and 18 were amplified in vitro, and t (14;18) specific sequences were detected in 1 of 14 primary cutaneous B-cell lymphomas, in 1 of 14 primary nodal B-cell lymphomas and in none of 3 B-cell pseudolymphomas. These results indicate that the t (14;18) may occur in a small subset of primary cutaneous lymphoma. However, the difference in incidence of the t (14;18) between primary nodal and primary cutaneous lymphomas suggests that different molecular mechanisms are involved in the pathogenesis of these lymphomas.

Notes: A 47-year-old patient with the previous history of a giant cell tumor of the left femur presented with 3 cutaneous nodules located on the face. Histologic examination revealed skin metastases of a giant cell tumor of bone, with dermal and subcutaneous nodules characterized by multinucleate giant cells and mononuclear cells. The patient died 10 months later from widespread metastases to the lung and brain. A panel of enzymoand immunohistochemical markers reactive with osteoclastic, fibroblastic and histiocytic determinants was tested on the cutaneous lesions. The results indicated osteoclastic lineage of the multinucleate giant cells whereas the mononuclear cells showed features of fibroblastic differentiation. Cutaneous metastasis from a giant cell tumor of bone is an extraordinary event and so far has only been reported once.

Notes: The increasing use of new drugs in cancer therapy, especially growth factors, hormones, and chemotherapies resulted in several reports of unusual skin eruptions. We studied a patient with erythroderma who had received erythropoietin because of myeloma with tumor anemia. The histological features were characterized by a lichenoid, focally granulomatous infiltrate with predominance of histiocytes. It is important for dermatopathologists to recognize this interesting pattern induced by erythropoietin.

Notes: A 71-year-old woman under PUVA-treatment for mycosis fungoides developed erythematous patches around the nasolabial folds and papules on the chin with clinical features of perioral dermatitis. Histology showed a specific infiltrate of mycosis fungoides with predominance of medium to large-sized pleomorphic lymphocytes and immunoblasts. Immunohistochemical analysis revealed the T-phenotype of the neoplastic cells. Small clusters of B-lymphocytes could also be observed within the infiltrate. Perioral dermatitis-like lesions can be added to the spectrum of rare and unusual clinical manifestations of mycosis fungoides.

Notes: Interpretation of molecular analyses of cutaneous lymphoid infiltrates may be difficult because a heterogeneous group of cells is usually present within the neoplasms. Extraction of DNA from tissue sections does not provide exact information about which cell population has been analysed. We present a laser microscope system that allows selective molecular analysis of single cells or small groups of cells in cases of cutaneous lymphoma. An ultraviolet (UV)-laser microscope system (PALM, Wolfratshausen, Germany) was used to isolate particular populations of cells from a routinely processed specimen of a cutaneous follicular lymphoid proliferation. Using the UV-laser beam, a circle was cut around a target germinal centre in order to separate it from neighbouring tissues and to isolate a pure population of germinal centre cells. Isolated cells were scraped off with a micromanipulator and placed in a proteinase-K solution. DNA was extracted and amplified by the polymerase chain reaction (PCR) technique. Analysis of immunoglobulin JH gene rearrangement showed a distinct monoclonal band. In a second phase, using the same procedure in the same specimen, mantle zone cells around a germinal centre and single interfollicular B lymphocytes were isolated for PCR analysis of immunoglobulin JH gene rearrangement. In this population of cells, no clonality could be detected. This new technique allows the selective elimination of undesired cells and tissue from cutaneous neoplasms. By destruction of unwanted tissues with laser-beam energy a contamination-free sample is obtained. Analysis of isolated cells in our case demonstrated a clonal rearrangement derived from germinal centre cells and not from other B lymphocytes in the specimen, confirming the diagnosis of cutaneous follicle centre lymphoma. The method described has exciting implications for dermatology and dermatopathology, allowing precise correlation of morphological features with findings by molecular genetics.

Notes: Background  Benign melanocytic skin lesions may be difficult to differentiate from melanoma both clinically and dermoscopically. One of the most confounding dermoscopic features, commonly seen in melanoma but in our experience also in melanocytic naevi, is represented by the so-called blue–white structures (BWS).Objectives  To evaluate diagnostic significance and histopathological correlates of BWS seen by dermoscopy in a series of clinically equivocal melanocytic skin lesions that were excised.Methods  Patients were recruited from six specialized pigmented lesion clinics in Austria, Italy and Spain over a period of 9 months. All consecutive patients showing one or more melanocytic lesions with BWS, but not classified as melanoma dermoscopically, were included. Each lesion was photographed clinically and dermoscopically. All images were reviewed by one of us and the degree, type and location of BWS evaluated for each lesion. A panel of four experienced dermatopathologists independently reviewed all specimens for diagnosis and one of them evaluated presence and degree of melanosis and/or fibrosis. The main outcome measures were the percentage and histopathological correlates of lesions with different degree, type and location of BWS.Results  All included lesions with BWS (n = 158) showed partial or focal regression histopathologically. One hundred and thirty-five (85·4%) lesions were diagnosed as melanocytic naevi (complete histopathological interobserver agreement), whereas 23 (14·6%) were defined as equivocal because at least one of four pathologists diagnosed the given lesion as melanoma. Only one lesion was diagnosed as melanoma by all four pathologists. The majority of naevi exhibited blue areas (84·4%) with a central distribution (57%) and involving 〈 50% of the lesion surface (89·6%). By contrast, 78·3% of equivocal lesions revealed a combination of white and blue areas with an irregular distribution (60·9%) and involving 〉 50% of the lesion surface (47·8%).Conclusions  Using degree and type of BWS, an algorithm was constructed that can be applied for the management of lesions exhibiting dermoscopic features of regression.

Notes: A specific molecular probe for the malignant lymphoid clone of lesions of a patient with mycosis fungoides was developed. As a clone-specific marker the junctional region of rearranged T-cell-receptor-gamma (TCR-γ) genes was used. An oligonucleotide primer complementary to these sequences was designed. Using this primer and polymerase chain-reaction technology, early hypopigmented lesions of the patient, which were previously unclassifiable by conventional microscopy, were analysed. The study demonstrates, on the molecular level, that these hypopigmented lesions contain tumour clone-specific DNA and may represent early manifestations of mycosis fungoides.