Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a neoplasm derived from precursors of plasmacytoid dendritic cells. Cutaneous involvement represents often the first manifestation of the disease. We studied 45 skin biopsies from 33 patients (M:F=7.25:1; median age: 71 y; age range: 30 to 89) with BPDCN to delineate histopathologic and immunophenotypic features of this disease. Patients presented with generalized (n=18), localized (n=6), or solitary (n=9) macules, plaques, and/or tumors. Staging investigations at presentation were negative in 20 patients. Unusual histologic features included a perivascular/periadnexal pattern (6 biopsies from 4 patients) and the presence of pleomorphism of neoplastic cells with blastoid cells admixed with elongated, twisted, or hyperchromatic cells (observed in 24 specimens). Negativity of 1 among the 4 markers CD4, CD56, CD123, and TCL-1 was seen in 11 biopsies, and of 2 markers in 4 biopsies. Staining for CD68 revealed positivity of the majority of cells in 1 and of scattered cells in 24/37 stained cases. Terminal deoxynucleotidyl transferase was observed in 22/37 stained cases. Staining for Bcl-6, MUM-1 and FOX-P1 revealed positivity of a variable proportion of neoplastic cells in 16/30, 19/29, and 21/23 cases, respectively. Our study shows that cutaneous lesions of BPDCN display a greater variability of morphologic and phenotypic features than recognized earlier. Discrete perivascular infiltrates, pleomorphic morphology of neoplastic cells, and unusual phenotypic profiles may be the source of diagnostic pitfalls. These atypical variants should be recognized to make an early diagnosis and to manage properly patients with this aggressive hematological disorder.

Background: this study aims to investigate the possible association among the histopathologic features of carotid plaque instability, the presence of micro- or macrocalcifications, the expression of in situ inflammatory biomarkers, and the occurrence of the major risk factors in this process in a large series of carotid plaques. Methods: a total of 687 carotid plaques from symptomatic and asymptomatic patients were collected. Histological evaluation was performed to classify the calcium deposits in micro or macrocalcifications according to their morphological features (location and size). Immunohistochemistry was performed to study the expression of the main inflammatory biomarkers. Results: results here reported demonstrated that calcifications are very frequent in carotid plaques, with a significant difference between the presence of micro- and macrocalcifications. Specifically, microcalcifications were significantly associated to high inflamed unstable plaques. Paradoxically, macrocalcifications seem to stabilize the plaque and are associated to a M2 macrophage polarization instead. Discussion: the characterization of mechanisms involved in the formation of carotid calcifications can lay the foundation for developing new strategies for the management of patients affected by carotid atherosclerosis. Data of this study could provide key elements for an exhaustive evaluation of carotid plaque calcifications allowing to establish the risk of associated clinical events.

In the last decade, several studies have reported an unexpected and seemingly paradoxical inverse correlation between BMI and incidence of cardiovascular diseases. This so called “obesity paradox effect” has been mainly investigated through imaging methods instead of histologic evaluation, which is still the best method to study the instability of carotid plaque. Therefore, the purpose of our study was to evaluate by histology the role of obesity in destabilization of carotid plaques and the interaction with age, gender and other major cerebrovascular risk factors. A total of 390 carotid plaques from symptomatic and asymptomatic patients submitted to endarterectomy, for whom complete clinical and laboratory assessment of major cardiovascular risk factors was available, were studied by histology. Patients with a BMI ≥ 30.0 kg/m2 were considered as obese. Data were analyzed by multivariate logistic regression and for each variable in the equation the estimated odds ratio (OR) was calculated. Unstable carotid plaque OR for obese patients with age < 70 years was 5.91 (95% CI 1.17–29.80), thus being the highest OR compared to that of other risk factors. Unstable carotid plaque OR decreased to 4.61 (95% CI 0.54–39.19) in males ≥ 70 years, being only 0.93 (95% CI 0.25–3.52) among women. When obesity featured among metabolic syndrome risk factors, the OR for plaque destabilization was 3.97 (95% CI 1.81–6.22), a significantly higher value compared to OR in non-obese individuals with metabolic syndrome (OR = 1.48; 95% CI 0.86–2.31). Similar results were obtained when assessing the occurrence of acute cerebrovascular symptoms. Results from our study appear to do not confirm any paradoxical effect of obesity on the carotid artery district. Conversely, obesity is confirmed to be an independent risk factor for carotid plaque destabilization, particularly in males aged < 70 years, significantly increasing such risk among patients with metabolic syndrome.