Applying immunohistochemical procedures for the detection of eight different cytokeratin (CK) polypeptides and other differentiation markers, we compared the staining patterns of normal cutaneous structures with those of benign adnexal tumors (n = 65). Syringomas exhibited a marker pattern highly reminiscent of that seen in normal dermal eccrine ducts (EMA in peripheral cells, CK 10 in intermediate cells, and CK 6, CK 19, and CEA in luminal cells). Nodular hidradenomas exhibited complex patterns suggesting relationship between tumor cells, including clear cells, and normal secretory coil cells (CK 7, CK 8, CK 19, and EMA); however, dermal-duct and epidermoid differentiation were also detectable. In both cylindromas and spiradenomas, zonal staining patterns were apparent: modified myoepithelial cells were positive for smooth-muscle-type actin, while the luminal cells mainly expressed ductal markers (CK 6 and CK 19) and, less prominently, secretory-coil markers including CK 7. Eccrine poromas exhibited a widespread reaction for CK 5/6 and EMA, analogous to peripheral dermal duct cells, but focal maturation toward inner-ductal and secretory-coil cells was also demonstrable. The staining pattern observed in trichoepitheliomas resembled that of the outer but not the inner root sheath. In conclusion, the detailed marker profiles obtained in the present study have broadened our understanding of the differentiation and nature of these highly singular tumor types.

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The awareness and the identification of the various histopathological presentations of FMF by pathologists, as well as by clinicians, are imperative to prevent diagnostic errors.

In this study, we investigated clinical features, aetiology, prospective follow-up results and also factors favouring secondary erythema nodosum (EN) in patients with EN. A total of 50 patients (mean age 38 y) with a diagnosis of EN between 1993 and 2002 in our clinic were included in the study prospectively. A biopsy was performed in 30 of the patients. Patients were considered to have secondary EN when an underlying condition was found, and to have primary (or idiopathic) EN when no such condition was found. For the diagnosis of the underlying diseases, diagnostic criteria and/or diagnostic methods were used. Categorical variables were compared by using chi2 test. The majority of the patients were female (6F/1M) and 54% of cases had a determined aetiology. The foremost aetiology was primary tuberculosis (18%) followed in decreasing order by a poststreptococcal (16%), sarcoidosis (12%), inflammatory bowel diseases (IBD) (4%), Behçet's disease (2%), and pregnancy (2%). All the patients were followed for a mean duration of 7 y. The nodosities relapsed every y in 74% of idiopathic EN patients but in only 1 (Behçet's disease) of the secondary ones. Factors favouring secondary EN were as follows: prolonged fever, cough, sore throat, not relapsing EN, abnormal chest X-ray, leukocytosis, an erythrocyte sedimentation rate of higher than 50 mm/h and a CRP value of higher than 6 times the upper limit of normal. All the patients had bed rest and the majority was given naproxen. The outcomes were usually favourable within 7 d. The patients with an underlying disease were given specific treatment. EN has been associated with numerous diseases. In order to reduce cost and duration of diagnosis, every centre should determine its own most frequent aetiological factors. Factors favouring secondary EN should also be determined. Our study revealed primary tuberculosis, streptococcal pharyngitis, sarcoidosis, IBD, and Behçet's syndrome as the main aetiologies of EN.

The differential diagnosis of psoriasis affecting palmoplantar skin might be troublesome because of the anatomic properties of this region. Both palmoplantar psoriasis and eczematous dermatitis of this skin area share similar histologic features. The punch biopsies from 17 patients with psoriasis and 25 with eczematous dermatitis were evaluated, blind to the clinical diagnosis. Vertically situated multiple foci of parakeratosis, alternating with orthokeratosis, were the only statistically significant feature in the differential diagnosis of palmoplantar psoriasis [76.5% (13/17), p ¼ 0.005]. In contrast, multiple foci of parakeratosis [70.6% (12/17)], loss of granular layer at least in focal areas [41.2% (7/17)], presence of neutrophils at the summits of parakeratosis [4% (1/17)], presence of neutrophils and/or plasma in the parakeratotoic foci [94.1% (16/17) and 11.8% (2/17)], psoriasiform epidermal hyperplasia [88.2% (15/17)], spongiosis restricted to the lower parts of the epidermis [47.1% (8/17)], dyskeratotic cells [82.4% (14/17)], thinning of suprapapillary plate [58.8% (10/17)], edema of the papillary dermis [29.4% (5/17)], presence of tortous and dilated capillaries in the papillary dermis [52.9% (9/17) and 76.5% (13/17)] and extravasated erythrocytes [29.4% (5/17)] were found to be more common in palmoplantar psoriasis compared with eczematous dermatitis; but none of them was statistically significant. Interestingly, spongiotic vesicles were seen in most of the patients with psoriasis [76.5% (13/17)]. In conclusion, according to our findings, many features of palmoplantar psoriasis overlapped with those of eczematous dermatitis. However, detection of multiple parakeratotic foci, placed vertically, alternating with orthohyperkeratosis, could be considered in favor of palmoplantar psoriasis. Aydin O, Engin B, Oguz O, _Ilvan S x, Demirkesen C. Non-pustular palmoplantar psoriasis: is histologic differentiation from eczematous dermatitis possible?