Keloidal basal cell carcinoma: not a distinctive clinicopathological entity.

BACKGROUND: Keloidal basal cell carcinoma (BCC) has been reported as a rare but distinctive variant of BCC. OBJECTIVES: To determine the frequency of keloidal collagen in BCC and to correlate it with clinical, histopathological and immunohistochemical features. METHODS: Over 12 months, all cases of BCC with thick sclerotic collagen were collected and studied for clinical diagnosis, site, histopathological features and immunohistochemistry (collagen I, III, IV, laminine) in comparison with five keloids. RESULTS: Of 1011 BCCs seen, 18 showed thick sclerotic collagen. In two cases, these stained positive for collagen type IV or laminine, indicating basement membrane material. In 16 cases, sclerotic bundles stained positive for collagen type I but not for types III, IV, and laminine, as do keloids. The clinical diagnosis was BCC (13), squamous cell carcinoma (one) or keloid (one). Fourteen lesions came from the face, nine of them from the ear. Keloidal collagen was extensive in 10 lesions, including all from the ear. Histologically, tumours often had morphoeiform zones (14), necrosis en masse (eight) and ulceration (nine). CONCLUSIONS: Keloidal collagen in BCC is not as rare as reported and consists of type I collagen, the same as in keloids. It does not characterize a distinctive clinicopathological entity but is found in different histological types of BCC with varying clinical appearance. Keloidal collagen in BCC is associated with morphoeiform features, ulceration and necrosis. Interestingly, extensive keloidal collagen is more often seen in BCC on the ear, a site prone to develop keloids.

Pseudoclonality in cutaneous pseudolymphomas: a pitfall in interpretation of rearrangement studies.

BACKGROUND: Pseudoclonality is a well-known problem in the interpretation of rearrangement studies of lymph node biopsies. Recently, pseudoclonality has been demonstrated in skin lesions of borreliosis. Studies on pseudoclonality in cutaneous pseudolymphomas are lacking but pseudoclones may pose a risk for overinterpretation of such lesions as cutaneous lymphoma. OBJECTIVES: To determine the frequency of pseudoclonality in cutaneous pseudolymphomas identified by clinicopathological correlation and follow up. METHODS: Study of 30 lesions of pseudolymphomatous cutaneous infiltrates (including insect bite reactions, borrelial pseudolymphomas and pseudolymphomatous drug eruptions) by histopathology, immunophenotyping, T-cell receptor gamma rearrangement and IgH rearrangement. RESULTS: Seven infiltrates were B-cell pseudoclonal; four were T-cell pseudoclonal. Moreover, B-cell clonality was identified in four cases. Immunophenotyping demonstrated that B-cell pseudoclonality and B-cell clonality occurred when infiltrates were moderately dense and included only a minority of B lymphocytes. T-cell pseudoclonality also occurred mostly in moderately dense infiltrates. CONCLUSIONS: B-cell and T-cell pseudoclones are not uncommonly encountered in moderately dense pseudolymphomatous infiltrates (23% and 13%, respectively). B-cell clonality is seen occasionally in pseudolymphomatous infiltrates (13%), especially when they are sparse in B lymphocytes. Therefore, rearrangement studies cannot be interpreted without correlation with morphological patterns and immunophenotyping of infiltrates and they need to be confirmed by duplicate or triplicate tests in order to prevent overinterpretation.

Desmoplastic trichoepithelioma versus morphoeic basal cell carcinoma: a critical reappraisal of histomorphological and immunohistochemical criteria for differentiation.

AIMS: It is often difficult to differentiate between cases of desmoplastic trichoepithelioma (DTE) and morphoeic basal cell carcinoma (MBCC) because both lesions have many features in common. The aim was to clarify which criteria for differentiation offer the best basis for diagnosis. METHODS AND RESULTS: Nineteen cases of DTE were compared histologically and immunohistochemically with 18 cases of MBCC (using CD34, CD10, cytokeratin (CK) 20, androgen receptor, Bcl-2, Ki67 and p53 immunohistochemistry). Sensitivity, specificity and positive and negative likelihood ratios were calculated. Convincing diagnostic evidence for DTE was identified for the following features: symmetry, good circumscription, depression in the lesion's centre. However, these features are applicable only to excisional specimens, not to specimens taken by punch biopsy. Signs of infundibular, follicular or sebaceous differentiation, calcification, osteoma, association with a melanocytic naevus, and absence of solar elastosis below the lesion provided equally robust diagnostic evidence for DTE. Immunohistochemically, only staining of Merkel cells with CK20 and negativity of aggregations with androgen receptors were diagnostically convincing for DTE. Ki67 and p53 revealed significant differences, but a lower positive likelihood ratio. CONCLUSION: Histopathologistics need to identify with confidence subtle signs of infundibular, follicular and sebaceous differentiation because these features are dependable criteria to differentiate DTE from MBCC. Immunohistochemistry for androgen receptors and CK20 is helpful, but interpretation is difficult in some DTEs when few cells are immunopositive for these markers.

Erythema migrans: a reassessment of diagnostic criteria for early cutaneous manifestations of borreliosis with particular emphasis on clonality investigations.

BACKGROUND: Controversy exists about the relationship of borrelia infection with B-cell lymphomas because B-cell clonality has been identified in infiltrates that contained borrelia-specific DNA. Systematic clinicopathological, immunophenotypical and molecular pathological studies of early borreliosis are lacking. OBJECTIVES: (i) To clarify whether clonal B-cell populations are present already in early borreliosis of the skin (erythema migrans); (ii) to re-evaluate clinicopathological, immunophenotypical and molecular pathological criteria for diagnosis of erythema migrans. METHODS: Study of 34 patients with erythema migrans confirmed by polymerase chain reaction (PCR). Infiltrates were analysed by histopathological and immunohistochemical methods and multiplex PCR for clonal IgH rearrangements. RESULTS: Erythema migrans shows a broad spectrum of changes including sparse infiltrates of T lymphocytes, dense interstitial granulomatous infiltrates (CD68+), and pseudolymphomatous patterns with germinal centre formation. There were accompanying epidermal changes in 59% of patients, and plasma cells were an inconsistent finding. B cells were few when infiltrates were sparse, but increased disproportionately when infiltrates were dense. IgH rearrangement studies revealed one pseudo-oligoclonal, three pseudoclonal and three clonal infiltrates. Pseudoclonality was encountered when infiltrates contained only few B lymphocytes. CONCLUSIONS: Infiltrates in erythema migrans are dominated by T cells followed by CD68+ histiocytes and B lymphocytes. Plasma cells are an inconsistent finding. Pseudoclonality of IgH rearrangement is a result of infiltrates being sparse in B lymphocytes and represents a pitfall in molecular pathological diagnosis that can only be avoided by duplicate or triplicate tests. Incidental B-cell clonality may be encountered in patients with unequivocal erythema migrans and should not be interpreted as a malignant lymphomatous process induced by borrelia.

[Dynamic blood glucose adjustment in diabetics in a closed loop system]. / Dynamische Blutglukoseeinstellung von Diabetikern in einem geschlossenen Regelkreis.

An automatic regulator aep (artificial endocrine pancreas) has been developed for the extracorporeal blood glucose regulation. After glucose monitoring, the maschine steers an insulin infusion pump by means of adequate algorithms to obtain a glucose balance in labile diabetic inpatients. This system, also called artificial beta-cell, is a closed loop regulatory system with impulses from the actual blood glucose that represents true feedback principles. So far it is preferably used during surgical operations of labile diabetics and for the intensive therapy of patients with pancreatic affections. The clear therapeutic advantages, that have been found in some special medical centres, give hope that technical ways will be found to master the narrow passes and the difficulties in the future.

[Algorithm for extracorporal blood glucose regulation (author's transl)]. / Steueralgorithmus für die extrakorporale Blutglucoseregulierung.

A control mechanism is described, based on a simple proportional/differential regulation. The calculation takes one minute and it takes into account glucose degradation, insulin half life in vivo, and the delay between blood sampling and insulin action on the blood glucose value. This is repeated continuously every minute (short time mode) or every 5 minutes or more (long time mode), depending on the rate of change of the blood glucose. Operator decision is based on digitally converted tables, which are analogous to the graph of proportional control, and on glucose equivalent tables, which give the insulin effect on glucose as a function of time.

Blood glucose monitoring and computer regulation by means of an artificial endocrine pancreas.

Extracorporeal blood glucose regulation has been implemented by a closed-loop system (artificial endocrine pancreas, "aep") of our own construct. Simple, highly flexible algorithms have been developed that allow smooth repair of a deranged glucose imbalance up to a period of 125 hours.