Faculty Bibliography

This article reviews a group of skin disorders that have in common the presence of a cellular infiltrate with plasma cells upon histopathologic examination. These include inflammatory and neoplastic diseases and a group of miscellaneous disorders of varied etiology. The correlation between the presence of plasma cells in the cellular infiltrate and the diagnosis, prognosis, and pathogenesis of the disorders is emphasized.

A case is presented of a multifocal malignant neoplasm involving the skin of the upper back in a 10-year-old boy following radiation therapy to the head and neck for a cerebellar medulloblastoma. Histologically, the neoplastic cells were remarkable for the presence of abundant periodic acid-Schiff (PAS)-positive diastase-resistant intracytoplasmic eosinophilic granules. Immunoperoxidase procedures revealed strong positive staining of the tumor cells with desmin, vimentin, and smooth muscle myosin antibodies, and negative staining for myoglobin, S-100 protein and keratin, thus supporting a smooth muscle line of differentiation for this neoplasm. Electronmicroscopy demonstrated numerous intracytoplasmic autophagic vacuoles that corresponded to the granules observed under the light microscope. Leiomyosarcoma should be entertained in the differential diagnosis of poorly differentiated cutaneous neoplasms histologically characterized by a proliferation of cells containing abundant granular eosinophilic cytoplasm.

The term parapsoriasis refers to a group of chronic asymptomatic scaly dermatoses of unknown etiology about which there is still controversy over the nosology and nomenclature of the different conditions that comprise the group, particularly pityriasis lichenoides chronica (PLC) and small plaque parapsoriasis (SPP). In an attempt to establish the distinctive clinicopathologic features of these two dermatosis, we prospectively studied 44 patients who presented with the typical clinical and histologic picture of either of these two diseases. SPP was clinically characterized by scaly oval plaques on the trunk and proximal aspect of extremities. Spongiosis was the salient histopathologic feature, with absence of fibrosis or melanophages. PLC presented with a scaly papular eruption over the trunk and extremities and histologically was characterized by an interface dermatitis. We conclude that sufficient clinical and histologic features differentiate these two entities and we propose that the term parapsoriasis be used only to designate SPP and large plaque parapsoriasis.

Melasma is characterized by a facial hypermelanosis of light to dark brown color, being more common in women of Hispanic origin. In this study, 27 men with melasma were evaluated clinically and histologically to compare their features with those of previous studies. Three patterns of localization were recognized, namely, centrofacial, malar, and mandibular. On the basis of Wood's light examination, an epidermal, a dermal, and a mixed type were identified. Epidermal hyperpigmentation only and epidermal and dermal hyperpigmentation were found in histologic analysis of the cases. Significant etiologic factors included exposure to sunlight in 66.6% as well as a familial predisposition in 70.4% of the cases. This study demonstrated that melasma in men shares the same clinicohistologic characteristics as in women, but hormonal factors do not seem to play major significant role.

Various cutaneous signs and syndromes have been associated with hepatitis B virus infection. This is a report of the clinical, pathologic, immunofluorescence, and immunoperoxidase studies of peculiar papular lesions that have been observed to occur during the chronic phase of hepatitis B virus infection. A total of thirteen patients positive for hepatitis B surface antigen (HBsAg) were studied. Twelve had asymptomatic, recurrent, erythematous papular lesions localized on the back, chest, and proximal areas of the upper extremities that lasted 6 to 7 days. The histopathology of these skin lesions showed a superficial and deep perivascular dermal mononuclear cell infiltrate. Immunoperoxidase studies for HBsAg and direct immunofluorescence for IgG, IgM, IgA, and C3 showed negative results. An abnormal host response to viral antigens other than HBsAg is suggested as a possible mechanism responsible for appearance of these skin lesions.

Five patterns of natural pigmentary demarcation lines have been described, occurring most frequently in dark-skinned persons. We report the appearance of these lines on the lower limbs of four Puerto Rican women during pregnancy; the lines faded postpartum. Our findings document group B pigmentary demarcation lines that can completely regress postpartum as another less frequently recognized physiologic change of pregnancy.