Lymphomas

The diagnosis of lymphoma currently relies on a combination of clinical, routine histopathologic, and immunohistochemical studies, sometimes supplemented by other special techniques such as flow cytometry, DNA analysis, and gene rearrangement study. This review considers the practical diagnosis of cutaneous lymphoma, with particular emphasis on three areas: Hodgkin's disease, non-Hodgkin's lymphomas and their differentiation from lymphocytoma cutis, and mycosis fungoides and other T-cell lymphomas.

Cutaneous metastasis from papillary carcinoma of the thyroid gland

Cutaneous metastases from carcinoma of the thyroid gland are rare. We present the clinical, histologic, and immunohistochemical features of a solitary metastasis from papillary carcinoma of the thyroid. Our results indicate that this tumor can produce epithelial mucin and, therefore, must be differentiated from other metastatic carcinomas and from primary apocrine tumors of the skin. Positive staining for thyroglobulin confirmed the diagnosis in this case.

Lichenoid histopathologic changes in patients with clinical diagnoses of exfoliative dermatitis

Among 30 patients who received a clinical diagnosis of exfoliative dermatitis and were biopsied between 1982 and 1990, nine showed microscopic features of lichenoid dermatitis. Clinical information was available in eight of these cases. Possible etiologic factors included lymphoma, herpes simplex infection, connective tissue disease, and (in five cases) reactions to drugs. In each instance, microscopic features included a superficial perivascular lymphocytic infiltrate involving the dermal-epidermal interface, vacuolar alteration of the basilar layer, and individually necrotic keratinocytes at all levels of the epidermis. Such microscopic changes are not usually described in connection with exfoliative dermatitis, with the possible exception of those cases related to lichen planus or lupus erythematosus. Disseminated lichenoid drug eruption is one possible interpretation of the drug-induced cases. Erythema multiforme is another condition that has similar microscopic features and has been associated with drugs (many of which also cause exfoliative dermatitis), infectious agents, neoplasms, and connective tissue diseases. Lichenoid dermatitis can become generalized and clinically mimic and exfoliative dermatitis. Many, but not all, of these eruptions may be triggered by drugs.

Meningoceles, meningomyeloceles, and encephaloceles: a neuro-dermatopathologic study of 132 cases

Because there have been few comprehensive histopathologic studies of meningomyeloceles and related malformations, we undertook a systematic study of these lesions. One hundred and thirty two cases were obtained from our surgical pathology files; these included 38 meningoceles, 71 meningomyeloceles, and 23 encephaloceles. Tissue sections were stained with hematoxylin and eosin; special stains included trichrome, alcian blue, Fontana-Masson, Nissl, Holzer, and immunoperoxidase for glial fibrillary acidic protein. Epithelial changes included ulceration, atrophy, or nevoid hyperplasia of the epidermis, and loss of appendages. Mesodermal features included fibrous zones resembling dura, subarachnoid tissue or scar (99% of cases), increased numbers of blood vessels (83%), hypertrophy of arrector pili muscle (42%), lipoma formation (38%), and immature skeletal muscle fibers (5%) that rarely intermingled with neuropil-like matrix. The latter tissue was identified in 71% of cases and included neurons, astrocytes, oligodendroglia, and ependyma. Forty-eight percent of cases included peripheral nerve fibers or roots, and some fibers formed onion bulb or Pacinian corpuscle-like structures. Meningothelial cells were observed in 26% of cases and sometimes formed recognizable whorls. Choroid plexus was noted in 3 cases, one example showing an unusual dystrophic calcification that formed long parallel spicules. Pigmented dendritic cells were observed within zones of fibrous tissue in 10% of cases. These malformations involve complex arrangements of cutaneous, neuroectodermal, and mesodermal elements. Because they may be encountered by dermatopathologists, familiarity with the microscopic features of dysraphic lesions is essential.

Effects of oxidants on lens transport

Hydrogen peroxide is associated with the development of cataracts. As an oxidant, it can act on the sulfhydryl groups of proteins and alter the transport properties of membranes. A nearly impermeant sulfhydryl binding agent is p-chloromercuriphenylsulfonate (p-CMPS). The changes in the current-voltage relationship of the equatorial potassium current produced by hydrogen peroxide and p-CMPS are similar. The authors studied the effects of p-CMPS to determine the possible effects of binding extracellular sulfhydryl groups. With a vibrating probe and microelectrodes, the authors saw three sequential effects of 0.5-5.0 microM p-CMPS. The first phase was a shift of the reversal potential, which is equivalent to the potassium equilibrium potential, to more negative values. The current-voltage relationship (J vs PD) shifted in a manner opposite to that produced by ouabain. The 86Rb uptake was stimulated. Ouabain blocked this initial phase. The second phase was a decrease in the resistance. The effects seen were similar to those described in other tissues after the intracellular injection of small amounts of Ca++. This second phase was inhibited by the removal of Ca++ from the medium and also by the addition of quinine to the medium. The third phase consisted of a depolarization of the lens. This effect has been described by others with larger concentrations of p-CMPS and is accompanied by an influx of Na+ and Ca++. The results suggested that micromolar quantities of extracellular p-CMPS sequentially stimulate the Na, K-pump; activate Ca(++)-dependent K+ channels; and open nonspecific channels. It is suggested that the second phase may play a role in cateractogenesis.

Rainfall and reproduction in females of the tropical lizard Mabuya striata striata

The reproduction of females of the lizard Mabuya striata striata was studied at two sites in Central Africa in an area with distinct rainy and dry seasons. The two sites differed in the amount of rain received. At the wetter site, a high proportion of M. s. striata were reproductive at all seasons. At the drier site, a high proportion of females were reproductive during the rainy season, but fewer were reproductive during the dry season. In addition, clutch size was lower at the drier site in the dry season. At both sites, low rainfall during the dry season appeared to constrain reproduction, but this constraint was greater at the drier site. At both sites, abdominal fat bodies were large during the rainy season and the early dry season and much smaller in the late dry season. In the early dry season abdominal fat bodies were larger at the drier than the wetter site. Females at the drier site apparently channel energy differentially into adult survival rather than present reproduction.

Congenital midline hamartoma: case report with histochemical and immunohistochemical findings

We report the case of a polypoid nodule on the chin of an infant. Microscopically, the lesion featured numerous pilosebaceous units, eccrine sweat glands, arrectores pilorum muscles, mature adipose tissue, and prominent admixtures of skeletal muscle. This lesion has much in common with the accessory tragus, and is similar to the one reported earlier as rhabdomyomatous mesenchymal hamartoma. We feel the more general term congenital midline hamartoma is preferable, as it encompasses both the clinical and microscopic features of the lesion.

Fatty acid alterations and carboxylase deficiencies in the skin of biotin-deficient rats

Full-thickness biopsies of haired and alopecic skin of biotin-deficient rats had less subcutaneous fat and showed lipophilic follicular plugging, vascular engorgement, epidermal hyperplasia, and abnormal keratinization. Mean activities of the three mitochondrial biotin-dependent carboxylases in the skin of biotin-deficient animals were reduced to 3-18% of control whereas the cytosolic enzyme, acetyl-CoA carboxylase, was reduced only to 38-61%. The total fatty acid content of haired and alopecic skin of deficient rats was 30% of those in the corresponding skin sites of control animals. Skin from deficient rats contained less of several long-chain fatty acids (16:0, 16:1, 18:0, 18:1, and 18:2) and more very-long-chain fatty acid, particularly 24:1 and 26:1. These alterations in fatty acids in biotin-deficient rats suggest that the skin findings in biotin and biotinidase deficiencies in humans may be due to similar fatty acid changes.

EGTA modulates equatorial currents in frog lenses

A combination of a vibrating probe with microelectrodes was used to study the effects on the equatorial K+ current, J, of perturbing the frog lens by removing Ca2+ from the bathing medium. The results were different in the absence and presence of EGTA. In the absence of EGTA the reversal potential (PDJ = 0) remained near the Nernst potential; the input resistance, R, and the resistance of the segment of the K+ current loop being studied, RJ, decreased; the driving force (PD - PDJ = 0) increased; and J increased fourfold. In the presence of EGTA J did not increase more than twofold; the current-voltage relationship became linear; RJ did not decrease and both the PD and the reversal potential, PDJ = 0, became less negative with time. These findings, which are dependent on the use of the vibrating probe, were unexpected, and they were explored by studying the effects of removing Na+ from the medium. Substituting TMA for Na+ did not increase J. Removal of Ca2+ and the addition of EGTA to a Na+-free medium in which frog lenses were bathed resulted in a decrease in RJ, and an increase in J; J varied inversely with the concentration of Na+ in the medium. The changes were reversible. A mechanism to account for the changes is proposed.

Infection-induced panniculitis

We evaluated the histopathologic findings in 15 cases of panniculitis due to infection. Organisms were identified by special staining in 14 cases, and in 6 of these the etiologic agent was confirmed by culture studies. In one additional case, lesional culture was positive despite negative special staining. Eight cases were caused by gram positive or gram negative bacteria, 2 by atypical mycobacteria, 2 by Nocardia, and 3 by fungi (Candida and Fusarium species). Most patients had conditions or were receiving therapies predisposing to immunosuppression, but at least 2 individuals had no other major medical problems. There were some variability in microscopic findings and overlap with established forms of panniculitis; 3 cases (2 due to bacteria and 1 to Fusarium) resembled acute, "neutrophilic" erythema nodosum, and evidence of vasculitis was seen in septicemias due to Pseudomonas, Nocardia, and Fusarium. Nevertheless, several distinctive features associated with infectious panniculitis of diverse etiologies included: epidermal alterations such as acanthosis and parakeratosis; dermal edema with a diffuse or perivascular neutrophilic infiltrate; and mixed septal-lobular panniculitis with neutrophilic infiltration, vascular proliferation and hemorrhage, and necrosis. Infection should be suspected in virtually any case of panniculitis, particularly when occurring in an immunosuppressed patients, but the microscopic features enumerated above should arouse particular suspicion of an infectious process.

Cranial fasciitis

We present the clinical, roentgenographic, light-microscopic, immunohistochemical, and ultrastructural findings in two children with cranial fasciitis. A 7-year-old boy and a 3-year-old girl presented with rapidly expanding masses on the scalp. Roentgenographic studies showed erosion of the underlying cranium in one case. Both lesions showed proliferations of elongated spindle cells in a focally myxoid matrix, together with areas of hemorrhage, vascular proliferation, and chronic inflammation. Occasional cells with atypical nuclei were observed, but mitotic figures were uncommon. Immunoperoxidase studies showed negative or equivocal staining for desmin, factor VIII-associated antigen, S100 protein, and macrophage antigen. In one lesion there was focal positivity for alpha 1-antichymotrypsin, and in another lesion, some cells stained positively for smooth-muscle actin. Electron microscopy showed cells with dilated endoplasmic reticulum, bundles of microfilaments, pinocytotic vesicles, and focal external membrane material, features of myofibroblasts. Both lesions were excised and there has been no recurrence in 7 years in one case and 1 year in the other case. Cranial fasciitis is closely related to nodular fasciitis, but it has a predilection for the scalp of children. Despite its rapid growth, it has a benign clinical course and is cured by excision with or without curettage of the underlying bone. Our immunohistochemical and ultrastructural observations indicate that, like nodular fasciitis, cranial fasciitis represents a proliferation of fibroblasts and myofibroblasts.

Eosinophils in skin lesions of erythema multiforme

To investigate the controversy regarding the presence of eosinophils in skin lesions of erythema multiforme, we undertook a retrospective clinicopathologic study of 19 recent cases that fulfilled clinical and histopathologic criteria for the disease. At least a few eosinophils were observed in 13 of 19 cases, and in four cases there were more than three per high-power field, qualifying as "tissue eosinophilia." Immunofluorescence studies in three cases with eosinophils failed to show the linear basement membrane zone fluorescence characteristic of bullous pemphigoid. Giemsa stains revealed that mast cells were present in lesions both with and without eosinophils. The only clinical features that distinguished patients with tissue eosinophilia from those without were an older age of incidence and a longer duration of disease prior to biopsy. Drugs were implicated as a causative factor in some patients both with and without eosinophils, but all four patients with tissue eosinophilia were believed to have drug-induced disease. We conclude that eosinophils do occur in skin lesions of erythema multiforme and are occasionally numerous.

What's new in dermatopathology

This article reviews the recent English language literature on dematopathology, with an emphasis on publications appearing between January 1986 and July 1987. Immunohistochemistry continues to grow in importance as a diagnostic as well as a research technique. The advent of in situ deoxyribonucleic acid hybridization technology has raised diagnostic accuracy to a new level; it has already proved valuable in the diagnosis of certain viral infections. Areas that have received particular attention include phenotypic characteristics of lymphomas and lymphoma-like conditions, congenital melanocytic nevi and malignant melanoma, neuroendocrine carcinoma and other small cell tumors of the skin, sweat gland carcinomas, and eosinophil and its associated diseases, and unusual infectious diseases involving the skin.

Cutaneous cytomegalovirus infection in a liver transplant patient. Diagnosis by in situ DNA hybridization

A 39-year-old woman who had cryptogenic cirrhosis and who had received two liver transplants developed necrotic skin lesions over the chest, upper arms, and thighs. Biopsy showed enlarged endothelial cells with intranuclear and intracytoplasmic inclusions characteristic of cytomegalovirus (CMV) infection. However, a few multinucleated gaint cells were observed beneath a necrotic epidermis. This, combined with the clinical presentation, suggested to infectious disease consultants an infection with herpes simplex virus. Using the immunoperoxidase technique, inclusions stained positively with antibody to CMV and showed a negative reaction for herpes simplex antigen. In situ hybridization using biotinylated DNA probes on formalin-fixed, paraffin-embedded tissue sections confirmed the diagnosis of CMV infection and failed to substantiate infection with herpes simplex virus. Subsequently, blood cultures became positive for CMV. The early recognition of CMV infection in the skin permitted institution of antiviral therapy with gancyclovir. Specific skin lesions of CMV infection are likely to be encountered with increasing frequency among immunosuppressed patients. Lesions may be vesicular, and epidermal multinucleated giant cells can occasionally be identified. In situ hybridization is a technique that is readily adaptable to surgical pathology laboratories and permits both a rapid, specific diagnosis and the early institution of appropriate therapy.

Effect of ouabain on lens equatorial currents

The equatorial potassium current measured with the vibrating probe is a segment of the potassium electrical loop. The equatorial current, J, was measured simultaneously with the PD and with the response to an injected current, I. The injection of sufficient inward current, I, made the PD more negative and increased the electrical gradient so that the current J became zero. The PD at which this occurs (PDJ-0) is the reversal potential. Following treatment with ouabain, the PD and PDJ-0 both become less negative. Since the driving force for the current, J, is equal to the difference between PD and PDJ-0, J may increase, stay the same or decrease depending on the relative changes in PD and PDJ-0. In the presence of ouabain, the PDJ-0 changes in parallel with or more rapidly than the PD.

Cutaneous involvement of multiple myeloma and extramedullary plasmacytoma

We recently performed a retrospective clinicopathologic study of five patients with cutaneous involvement of multiple myeloma or extramedullary plasmacytoma. Cutaneous nodules without extension from an underlying bony focus of disease developed in each case. In two cases skin lesions occurred in the more common setting of advanced disease, but in two others skin lesions provided early clues to the diagnosis. In three patients the appearance of skin lesions heralded a rapidly deteriorating clinical course, but two other patients had reasonably long survivals despite cutaneous disease (6 and 3 years, respectively). Two histopathologic configurations were identified in cutaneous lesions: nodular and infiltrative. Both patients with the latter form had multiple myeloma. In all cases tumor cells were pyroninophilic. Immunoperoxidase studies on fixed, paraffin-embedded tissues confirmed the electrophoretic findings in two cases, but findings were equivocal in three others. In one case, cells were positive for epithelial membrane antigen, and in another, alpha 1-antichymotrypsin-positive cells were observed in the centers of tumor islands. Cutaneous involvement with plasma cell neoplasms is recognized infrequently. Immunohistochemical techniques may prove to be valuable in evaluating these cases, but they are not without technical and interpretative difficulties.