Peroxidase activity in human cutaneous mast cells: an ultrastructural demonstration.

An intense and reproducible peroxidase staining in the cutaneous mast cells of two patients with systemic mast cell disease and urticaria pigmentosa is demonstrated at the ultrastructural level. This enzyme activity was demonstrated by use of a cytochemical technique employing 3,3'- diaminobenzicine (DAB) as an oxidizable substrate, after fixation by a tannic acid-aldehyde mixture. Enzyme activity was localized in the perinuclear cisterna and strands of endoplasmic reticulum. Granules appeared unreactive. This peroxidase activity appears sensitive to fixation by aldehydes; it is inhibited by 3-amino-1,2,4-triazole (AMT) and by lack of H2O2 or DAB in the incubation medium. These characteristics are fundamentally different from the peroxidase activity of basophils, and the demonstration of this enzyme is therefore not a further argument for a common ontogenetic origin of both cells. On the other hand, the cytochemical characteristics of this enzyme are very similar to those of platelet peroxidase (P-PO), which has been connected to the synthesis by platelets of prostaglandins. Since the mast cell is known to generate prostaglandins, the relationship between the enzyme described and prostaglandin synthesis by mast cells is discussed.

Morphologic diversity in malignant melanomas.

A review was conducted of 335 malignant melanomas to identify variant morphologic patterns that might be confused with other tumors. In all, 27 predominantly amelanotic neoplasms with unusual histologic features were selected for additional study. These included nine with an adenoid or pseudopapillary pattern, seven small cell neoplasms, five with prominent myxoid stroma, four with a hemangiopericytoma-like appearance, and two composed of neoplastic cells with a signet-ring configuration. A diagnosis of melanoma was confirmed in all cases by Fontana-Masson strains for melanin pigment, electron microscopic examination, or the results of immunohistochemical analyses for cytokeratin, vimentin, S-100 protein, and the HMB-45 antigen. One tumor was associated with a congenital hairy melanocytic nevus, five were vulvovaginal lesions, four arose in the sinonasal tract, and one occurred in the rectum. Four of the specified microscopic patterns were observed in both primary and secondary neoplasms; the two signet-ring cell melanomas were recurrent lesions. The authors conclude that malignant melanomas may assume the histologic guise of adenocarcinomas, small cell carcinomas, and sarcomas, in a variety of tissue sites. Special studies designed to detect melanocytic differentiation are therefore appropriate in diverse differential diagnostic settings.

Sebaceous gland hyperplasia of the vulva: a case report.

A unique case of sebaceous gland hyperplasia presenting as polypoid lesions on the vulva of a 32-year-old white woman is reported. Sebaceous hyperplasia is a benign condition most frequently seen on the forehead of elderly patients. The reported case presented with three soft, nontender polypoid lesions located on mons veneris and right labium majus. Histological examination showed hyperplastic sebaceous lobules not associated with hair follicles. The extremely rare site of the lesion, the clinical and histopathological differential diagnosis, and a therapeutical approach are discussed.

Magnetic resonance imaging in cavitary choroidal melanoma.

PURPOSE: To report the development of a cavitary choroidal melanoma in a patient with nevus of Ota and describe its magnetic resonance imaging (MRI) features. PATIENT: A 66-year-old man with right oculodermal melanocytosis and an ipsilateral choroidal cavitary melanoma was seen. Diagnosis was suspected on the clinical, ultrasonographic and MRI findings. RESULTS: T1-weighted image showed a hyperintense solid mass containing hypointense cystic-like spaces delineated by hyperintense septa with respect to the vitreous. The reverse image was observed on T2-weighted images. A choroidal melanoma comprising epithelioid and spindle cells with multilocular cavities was documented histopathologically. CONCLUSIONS: There may be an association between cavitary melanoma and nevus of Ota. Characteristic MRI findings could be helpful in the differential diagnosis of cavitary uveal melanoma.

Fine needle aspiration biopsy of myxoid metastasis of malignant melanoma.

The cytopathologic features of the fine needle aspiration biopsy of a myxoid metastasis of a cutaneous malignant melanoma are documented. The cytologic findings included fusiform-to-round cells with elongated cytoplasmic processes, fibroblastlike cells and inflammatory cells in a characteristic amorphous background substance. Immunocytochemical staining for S-100 protein was positive. The cytologic findings correlated well the histologic, histochemical, immunohistochemical and ultrastructural studies of the neoplasm. The cytologic differential diagnosis between metastases of malignant melanoma and other myxoid tumors of soft tissues is discussed.

Epithelial-myoepithelial carcinoma of the salivary gland. Fine needle aspiration cytologic findings.

A case of epithelial-myoepithelial carcinoma of the salivary gland in a 78-year-old patient is presented. Fine needle aspiration cytologic smears showed a moderate number of tumor cells arranged in three-dimensional, well-outlined clusters reminiscent of the ball-like structures of adenoid cystic carcinoma. The nuclei were small and monotonous, with finely granular chromatin and small nucleoli. A large number of cells showed abundant clear cytoplasm; however, in some of the clusters the cytoplasms were very scant, again mimicking adenoid cystic carcinoma. Fragments of pale homogeneous acellular material, isolated or surrounding the cellular clusters, were another conspicuous finding.

[Pre-Sézary erythroderma developing into Sézary syndrome: apropos of 2 observations]. / Eritrodermia tipo "pre-Sézary" con evolución a síndrome de Sézary: a propósito de dos observaciones.

Two cases of pre-Sézary erythroderma of several years of evolution that evolved into Sézary syndrome are presented. The role of persistent antigenic stimulation in the development of T-cell lymphoproliferative disease in discussed. We also review the different therapeutic approach to Sézary syndrome.

[Metastatic Crohn disease of the scrotum]. / Enfermedad metastásica de Crohn en escroto.

We report herein a rare case of metastatic Crohn's disease involving the penile and scrotal skin in a 56-year old man. We review the literature about this rare entity and describe its clinicopathological characteristics.

[Sea-blue histiocytes in a patient with mycosis fungoides]. / Histiocitos azul marino en un paciente con micosis fungoide.

The syndrome of the sea-blue histiocyte is a multisystemic infiltration by a special kind of macrophages which contain a ceroid material within its cytoplasm. We report herein a patient with mycosis fungoides, hyperlipidaemia type IIB and sea-blue histiocytes on bone marrow. Moreover, the cutaneous histopathology showed focus of eosinophilic spongiosis, that have not been previously described in mycosis fungoides, as far as we know.

[Dyshidrosiform pemphigoid]. / Penfigoide dishidrosiforme.

We report herein a new case of dyshidrosiform pemphigoid. Although vesiculo-bullae on palms or soles are frequent components of bullous pemphigoid, they are rare as a presenting phenomenon. In our opinion, dyshidrosiform pemphigoid should not be regarded as a distinctive form of localized pemphigoid.

[Gangrenous pyoderma associated with subcorneal pustular dermatosis (Sneddon-Wilkinson disease)]. / Pioderma gangrenoso asociado a dermatosis pustulosa subcórnea (enfermedad de Sneddon-Wilkinson).

This case report describes the simultaneous occurrence of pyoderma gangrenosum and subcorneal pustular dermatosis. They are both neutrophilic dermatoses that have been described associated in several instances. The association of pyoderma gangrenosum and other cutaneous diseases is also reviewed.

Reactive and malignant "angioendotheliomatosis": a discriminant clinicopathological study.

In order to determine whether or not phenotypic differences existed between reactive angioendotheliomatosis (RAE) and malignant angioendotheliomatosis (MAE), we studied the histological and immunohistochemical features of 4 and 8 cases of these lesions, respectively. Antibodies to leukocyte common antigen (LCA), specialized B- and T-lymphocytic determinants, Factor VIII-related antigen (FVIIIRAG), blood group isoantigens A, B, and H (BGI), epithelial antigens, vimentin, and actin; and Ulex europaeus I lectin (UEL) were utilized. Cutaneous lesions in all cases of MAE were part of a disseminated, fatal, intravascular cellular proliferation, with highly atypical cytological features. Because one of the patients in this group had cardiac valvular vegetations at autopsy, this case had been reported previously as representative of RAE. However, the latter example, as well as all others of MAE, stained strongly for LCA, B-cell antigens, and vimentin in tumor cells. FVIIIRAG was seen focally in 6 cases, in cells entrapped in platelet-fibrin thrombi; however, UEL binding and reactivity for BGI were uniformly absent. Conversely, RAE was typified by a cytologically-bland intravascular proliferation, with actin-positive, perivascular, pericytic cuffs. All 4 patients in this group had cutaneous involvement only, and the lesions tended to be self-resolving. One had pulmonary tuberculosis, but evidence for an underlying infection was absent in the remainder of RAE cases. Immunohistologically, RAE displayed universal reactivity for FVIII-RAG, BGI, UEL, and vimentin, and negativity for LCA in intravascular cells. Neither MAE nor RAE showed the presence of epithelial determinants. These data indicate that MAE and RAE are clinicopathologically distinct entities, showing lymphoid and endothelial features, respectively. Because of the phenotypic properties of the former condition, it would appear advisable to substitute the term "intravascular lymphomatosis" for "malignant angioendotheliomatosis".

Recognition of malignant melanoma by monoclonal antibody HMB-45. An immunohistochemical study of 200 paraffin-embedded cutaneous tumors.

Antibodies to S-100 protein have been used widely as markers of malignant melanoma, despite abundant evidence that they are non-specific for this neoplasm. Hence, alternatives to these reagents are desirable in diagnostic dermatopathology. We evaluated the characteristics of a new monoclonal antibody (HMB-45) which does have putative specificity for melanoma, and compared it with a polyclonal anti-S-100 reagent in immunohistochemical staining of 67 melanomas of the skin and 133 non-melanomatous cutaneous neoplasms. All specimens were formalin-fixed and paraffin-embedded, and were studied with the avidin-biotin-peroxidase complex technique. HMB-45 labelled 62 of 67 melanomas, while anti-S-100 recognized all tumors of this type. On the other hand, S-100 also was expressed by 15 of the non-melanocytic neoplasms, all 133 of which were HMB-45-negative. The only cases of melanoma that were missed by the latter reagent were of the spindle-cell type. Hence, HMB-45 was 100% specific and 93% sensitive, relative to a diagnosis of malignant melanoma in paraffin sections. Epithelioid and small-cell neoplasms are reliably recognized by this antibody, but it would appear that spindle-cell melanomas must be detected by other immunohistochemical means.

QBEND/10 (anti-CD34 antibody) in external root sheath cells and follicular tumors.

The human hematopoietic progenitor cell antigen (CD34) is a cell surface protein expressed by human hematopoietic progenitor cells, vascular endothelium, and many mesenchymal tumors. Sections from six samples of normal skin and from 41 epithelial tumors of the skin were studied. Immunostaining of epithelial cells from the external root sheath below the attachment of the arrector pili muscle and above the matrix cells was noted in normal samples. Tumors derived from or differentiated toward cells of the outer sheath, especially trichilemmomas, were immunostained with QBEND/10 (anti-CD34 antibody), whereas other epithelial tumors studied were negative. CD34 could serve as a marker of outer sheath cell derivation and may well be of value in the distinction between trichilemmomas and other lesions with similar histopathological features.

Malignant mixed tumor of the skin: malignant chondroid syringoma.

Malignant tumors of sweat gland origin are rare. Probably one of the rarest types, still poorly understood, is the so-called malignant chondroid syringoma or malignant mixed tumor of the skin. A case of malignant chondroid syringoma is presented. Ultrastructural study proves very useful for the differential diagnosis with other chondroid or chordoid tumors.