Light-chain-restricted germinal centres in reactive lymphadenitis: report of eight cases.

AIMS: Light-chain-restricted germinal centres are generally associated with the existence of a neoplastic lymphoproliferative disorder. The aim was to present a series of cases with persistent lymph node enlargement that featured some germinal centres showing light chain immunoglobulin restriction. METHODS AND RESULTS: A series of six reactive lymphadenitis and two Castleman's disease cases was analysed by immunohistochemistry, IgH-polymerase chain reaction (PCR) and microdissected PCR. In all cases some germinal centres contained a population of plasma cells and plasmacytoid germinal centre cells showing light chain immunoglobulin restriction. In three cases the monotypic cells also showed distinct Bcl-2 expression. Two of the cases showed a predominant IgH rearrangement on a florid polyclonal background and one had an IgH monoclonal rearrangement, as revealed by PCR. Microdissected germinal centre PCR revealed a dominant repeated band in one of three cases and in another case a non-repeated clonal peak was observed. One of the patients developed a follicular lymphoma, which became evident from a subsequent biopsy. CONCLUSIONS: These findings may be a manifestation of an underlying disorder in the regulation of the immune response, or an exaggeration of the germinal centre oligoclonal nature. This should be taken into account in the differential diagnosis of follicular hyperplasia.

Secondary amyloidosis associated with histiocytosis X.

We report a 34-year-old man diagnosed with Langerhans cell histiocytosis (LCH) or histiocytosis X in 1980. He had multiple focal osseous lesions, difficult control of the disease activity and was treated many times with chemo- and radiotherapy for symptomatic control. His kidney disease started 20 years after the diagnosis with progressive renal failure and increasing non-nephrotic proteinuria, coinciding with two flares of LCH. A percutaneous renal biopsy demonstrated amyloidosis. There is only one case described in the amyloidosis literature associated with LCH.

Small cell neuroendocrine carcinoma of the sinonasal region. A propose of a case.

We describe a 70-year-old man with rheumatoid arthritis and pulmonary fibrosis who presented with a month's history of pain in the left lateronasal region and inferior eyelid. On examination there was left exophthalmos, difficulty in coordinating eye movements, inflammation, erythema, and pain. Computed tomography showed a 3 cm mass in the left posterior ethmoid region, a biopsy specimen from which showed a small cell neuroendocrine tumour. He refused operation and was treated unsuccessfully with four cycles of cisplatin and etoposide.

CD133 expression in normal skin and in epithelial cutaneous tumors.

BACKGROUND: Expression of human CD133 (human prominin-1) in cancer cells has been postulated to be a marker of stemness and is considered as a putative marker of cancer stem cells (CSCs). We designed a study to describe the expression pattern of CD133 in normal skin and in epithelial cutaneous neoplasms. METHODS: The CD133 immunohistochemical expression of forty-three eccrine and apocrine tumors was compared to that observed in other epithelial tumors of the skin. In addition, flow cytometry was used to detect the CD133 expression of four epithelial skin neoplasms, including one porocarcinoma. RESULTS: CD133 immunoreactivity at the apical or at the apicolateral surface of cells forming glandular structures was observed. Cells from solid areas of benign or malignant tumors were not stained. The porocarcinoma derived culture cells showed a 22% of CD133 positive cells using flow cytometry, while squamous cell carcinoma cultures contained less than 0.1%. CONCLUSIONS: These observations indicate that CD133 is a specific marker of glandular differentiation that could be included in the diagnostic panel of cutaneous tumors with possible eccrine or apocrine differentiation. However, the use of CD133 expression as a marker of CSCs should be interpreted with caution in experiments of skin.