Epithelioid angiomatosis in HIV infection: neoplasm or cat-scratch disease?

Bacillary angiomatosis in an immunosuppressed dog

A dog being treated with immunosuppressive doses of prednisone and azathioprine for pancytopenia of unknown origin, developed, over a 2-week period, multiple erythematous nodular lesions in the skin including footpads. Skin samples revealed lesions identical to those of human bacillary angiomatosis (BA). The nodules were composed of multifocal proliferations of capillaries, each lined by protuberant endothelial cells. The capillary clusters were separated by an oedematous connective tissue, lightly infiltrated with degenerate inflammatory cells, including neutrophils and macrophages. Tissue sections stained with Warthin-Starry silver stain revealed large numbers of positively stained bacilli in the stromal tissue, most heavily concentrated around the proliferating capillaries. Lesions of vascular degeneration and inflammation were evident. Bartonella vinsonii subsp. berkhoffii genotype 1 was independently amplified and sequenced from the blood and the skin tissue. The pathognomonic nature of the histological lesions, demonstration of compatible silver-stained bacilli in the tissue, and identification of B. vinsonii subsp. berkhoffii in the blood and tissue indicates that this is most likely the aetiologic agent responsible for the lesions. Antibiotic therapy was successful in resolving the nodules. It would appear that B. vinsonii subsp berkhoffii, like Bartonella henselae and Bartonella quintana, has the rare ability to induce angioproliferative lesions, most likely in association with immunosuppression. The demonstration of lesions identical to those of human BA in this dog is further evidence that the full range of clinical manifestations of human Bartonella infection occurs also in canines.

Species-specific monoclonal antibodies for rapid identification of Bartonella quintana

Seven species-specific monoclonal antibodies (MAbs) to Bartonella quintana were produced and characterized. The MAbs were of the immunoglobulin G class and reacted only with 13 B. quintana strains in indirect microimmunofluorescence and Western immunoblotting assays. They did not react with eight other Bartonella spp., including Bartonella henselae, the most closely related species, and a selected MAb did also not react with nine other strains of gram-negative bacteria. The MAbs reacted mainly with a 34-kDa protein epitope of B. quintana which was shown to be species specific by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Four of five body lice experimentally infected with B. quintana were found to be positive for the organism in microimmunofluorescence assays with one MAb. These MAbs may provide a specific, simple, rapid, and low-cost tool for the identification of B. quintana and the diagnosis of infections due to the microorganism.

Bartonella spp. as emerging human pathogens

Members of the genus Bartonella (formerly Rochalimaea) were virtually unknown to modern-day clinicians and microbiologists until they were associated with opportunistic infections in AIDS patients about 6 years ago. Since that time, Bartonella species have been associated with cat scratch disease, bacillary angiomatosis, and a variety of other disease syndromes. Clinical presentation of infection with Bartonella ranges from a relatively mild lymphadenopathy with few other symptoms, seen in cat scratch disease, to life-threatening systemic disease in the immunocompromised patient. In some individuals, infection manifests as lesions that exhibit proliferation of endothelial cells and neovascularization, a pathogenic process unique to this genus of bacteria. As the spectrum of disease attributed to Bartonella is further defined, the need for reliable laboratory methods to diagnose infections caused by these unique organisms also increases. A brief summary of the clinical presentations associated with Bartonella infections is presented, and the current status of laboratory diagnosis and identification of these organisms is reviewed.

Bacterial infections

Non-opportunistic bacterial infections are an important cause of morbidity and mortality for HIV-infected adults and children. Factors associated with increased risk of these include altered B- and T-cell function; altered phagocytic cell function; skin and mucous membrane defects; and use of indwelling vascular catheters, antibiotics, or cytotoxic agents. The pathogens encountered most frequently are S. aureus, S. pneumoniae, H. influenzae, Salmonella sp., and Pseudomonas aeruginosa. Less commonly encountered organisms include Rhodococcus equi, Listeria monocytogenes, Shigella sp., and Nocardia asteroides, Strategies for prevention as well as diagnosis and treatment of these are discussed.

Adenomatoid Tumor of the Right Adrenal Gland in a Patient with AIDS

An autopsy case with an incidentally discovered adenomatoid tumor (AT) arising in the right adrenal gland of a 34-yr-old man with AIDS is presented. The immediate cause of death was disseminated coccidioidomycosis. The affected right adrenal gland was partially substituted by a firm 3.O cm nodule enclosed by cortical adrenal tissue. Histologically, the tumor had the typical appearance of those adenomatoid neoplasms described in the genital tract. The mesothelial origin of the neoplasm was confirmed by immunopositive cells for low weight cytokeratin and vimentin. Uncommon neoplasms in the adrenal glands of AIDS patients include leiomyosarcomas, leiomyomas, and malignant nerve sheath tumors. This report may represent the first case of an adrenal gland AT in a patient with AIDS, and probably the third well-documented histologically and immunohistochemically adrenal gland AT.

Bacillary angiomatosis in an HIV seronegative patient on systemic steroid therapy

Bacillary angiomatosis is an unusual systemic vascular proliferation seen predominantly in patients with the acquired immunodeficiency syndrome. These vascular lesions are due to infection with a Bartonella species, most commonly B. henselae, but sometimes B. quintana. It is treatable and often curable, but without therapy may be life-threatening. Clinically, the disorder often resembles several different vascular disorders, particularly pyogenic granuloma and Kaposi's sarcoma. We now report a clinically typical patient with bacillary angiomatosis who was HIV seronegative, but who had idiopathic thrombocytopenic purpura, was status-post splenectomy and to whom long-term systemic prednisone had been administered.

Bartonella (Rochalimaea) quintana infections

Bartonella (formerly Rochalimaea) quintana is the etiological agent of trench fever, a disease extensively reported during the World Wars. Recent molecular biology approaches have allowed dramatic extension of the spectrum of Bartonella infections. B. quintana is now also recognized as an etiological agent of fever and bacteremia, endocarditis, bacillary angiomatosis, and chronic lymphadenopathy. Human immunodeficiency virus-infected patients and/or homeless people are the most vulnerable to infection. Poverty and louse infestation were the main epidemiological factors associated with B. quintana infections during wartime. Although poverty and chronic alcoholism have been associated with modern cases of trench fever and bacteremia due to B. quintana in Europe and the United States, vectors for B. quintana have not been clearly identified and B. quintana has not been isolated from modern-day lice. Microscopic bacillary angiomatosis lesions are characterized by tumor-like capillary lobules, with proliferating endothelial cells. In vitro experiments have shown that B. quintana survives within endothelial cells and stimulates cell proliferation. These observations, together with the finding that lesions may regress when antibiotic therapy is administered, strongly suggest that B. quintana itself stimulates angiogenesis. Bartonella infections are characterized by a high frequency of relapses after brief courses of antibiotic therapy. It is to be noted that in vitro, although Bartonella species are highly susceptible to antibiotics, only the aminoglycosides have proved to be bactericidal. However, the most effective antibiotic regimen for Bartonella infections remains to be established.

Molecular approaches to the identification of unculturable infectious agents

New molecular biologic techniques, particularly representational difference analysis, consensus sequence-based polymerase chain reaction, and complementary DNA library screening, have led to the identification of several previously unculturable infectious agents. New agents have been found in tissues from patients with Kaposi's sarcoma, non-A, non-B hepatitis, hantavirus pulmonary syndrome, bacillary angiomatosis, and Whipple's disease by using these techniques without direct culture. The new methods rely on identifying subgenomic fragments from the suspected agent. After a unique nucleic acid fragment belonging to an agent is isolated from diseased tissues, the fragment can be sequenced and used as a probe to identify additional infected tissues or obtain extended portions of the agent's genome. For agents that cannot be cultured by standard techniques, these approaches have proved invaluable for identification and characterization studies. Applying these techniques to other human diseases of suspected infectious etiology may rapidly elucidate novel candidate pathogens.

Histological and ultrastructural study of one case of oral bacillary angiomatosis in HIV disease and review of the literature

Bacillary angiomatosis (BA) is a new clinicopathological entity defined as a pseudo-neoplastic capillary proliferation secondary to an opportunistic infection by one of two Rochalimaea sp.: R. quintana or R. henselae. Although BA is a recently recognised entity, numerous cases have been reported. Most of the patients affected are reported to have low absolute CD4 lymphocyte counts associated with AIDS. Yet, very few oral cases associated or not with cutaneous lesions have been reported or simply identified. Histopathological and ultrastructural features of one case of oral BA with gingival and palatal lesions are presented. Clinical aspects of oral BA do not hold pathognomonic features and the lesions may resemble either a reactive lesion of the gingiva, pyogenic granuloma or Kaposi's sarcoma. The lesion is characteristically composed of circumscribed lobular capillary proliferations and the presence of granular amphophilic material on haematoxylin and eosin sections surrounded by neutrophils and neutrophilic debris is a clue to diagnosis. Demonstration of bacilli in the interstitium by the Warthin-Starry silver method or, better, by electron microscopy is diagnostic. BA may contribute to the death of the patient but erythromycin has proved to be very effective treatment.

Bacillary epithelioid angiomatosis in acquired immunodeficiency syndrome (AIDS)--clinicopathological and ultrastructural study of a case with a review of the literature

Bacillary epithelioid angiomatosis (BEA) is a rare cutaneous disorder usually affecting patients with human immunodeficiency virus (HIV) infection often misdiagnosed as a vascular tumour. We describe a 51-year-old, HIV-positive, Caucasian, homosexual male who developed scattered papulo-nodular lesions with clinicopathological and ultrastructural features of BEA. He had a dramatic therapeutic response to systemic antibiotics. There has been a lack of such reports in the European literature. The differential diagnosis is discussed and a brief review of the English literature to date is included.

Immunohistochemical and electron microscopic profiles of cutaneous Kaposi's sarcoma and bacillary angiomatosis

Thirty cases of cutaneous Kaposi's sarcoma (KS) were evaluated and compared with eight cases of acquired immunodeficiency syndrome (AIDS)-related bacillary angiomatosis (BA). The morphologic features of both lesions were studied by light and electron microscopy and by immunohistochemistry with monoclonal endothelial antibodies against CD34, BNH9, and factor VIII-related antigen as well as the lectins Ulex europaeus 1 and Psophocarpus tetragonolobus. Macrophage/monocyte markers used were alpha 1-antitrypsin, lysosome, Kp1 (CD68), and polyclonal factor XIIIa. Electron microscopic studies demonstrated that most of the spindle cells in KS showed a paucity of cell organelles and an absence of Weibel-Palade bodies (WPB), whereas the cells in BA showed activated endothelial cells with WPB. By immunohistochemistry the spindle cells in KS were consistently positive for CD34 only, whereas proliferating cells in BA expressed all endothelial markers used. Numerous cells expressing macrophage/monocyte markers were present surrounding both KS and BA, and a small number of similar cells were entrapped within both lesions. The results demonstrated a restricted immunohistochemical profile for endothelial cell markers in spindle cells of KS (CD34+) distinct from that of endothelial cells in BA. These findings suggest that the spindle cells in KS are poorly differentiated endothelial cells or that they belong to an endothelial cell subset with partial expression of endothelial phenotype.

Polypoid endobronchial lesions. A manifestation of bacillary angiomatosis

Polypoid endobronchial lesions occurred in a patient with acquired immunodeficiency syndrome (AIDS) with recent fever, skin lesions, lymphadenopathy, lung infiltrates, and pleural effusions. His condition improved with antimicrobials and vincristine. After therapy ceased, skin lesions recurred and gastroesophageal mucosal lesions developed. Bacillary angiomatosis was identified during retrospective analysis of skin and endobronchial biopsy specimens.

Murine antibody responses distinguish Rochalimaea henselae from Rochalimaea quintana

Rochalimaea henselae causes persistent bacteremia, bacillary angiomatosis, and parenchymal bacillary peliosis. Detection of a specific antibody response to R. henselae infection may represent an alternative to cultivation as a means of diagnosis. We assessed the specificity of induced murine antibodies for antigens from R. henselae and the closely related species R. quintana. Groups of CD-1 mice were inoculated with whole organisms of six strains of R. henselae and two of R. quintana. Pre- and postinoculation blood specimens were collected. Enzyme immunosorbent assays were performed by using as antigens preparations of immunogenic proteins from one isolate of R. henselae or from the R. quintana type strain. These demonstrated high specificity of R. henselae-induced antibodies for proteins of R. henselae and of R. quintana-induced antibodies for proteins of R. quintana. Protein preparations extracted from all of the strains were separated electrophoretically. After their transfer to membranes, immunoblots were performed by using 1:1,000 dilutions of all of the pre- and postinoculation sera in combination with proteins from all of the strains. Preinoculation sera had minimal reactivity. All of the R. henselae-induced immune sera reacted with numerous proteins of all of the R. henselae strains but cross-reacted minimally with proteins of R. quintana. Immune sera from R. quintana-inoculated mice had similar species specificity. An immunofluorescence assay was developed by using antiserum to one strain of R. henselae. A 1:1,000 dilution yielded fluorescence with all strains of R. henselae but with none of R. quintana, Bartonella bacilliformis, or Afipia felis. Acinetobacter calcoaceticus subsp. anitratus was also unreactive with a dilution of 1:500. A 1:10 dilution yielded weak fluorescence with R. quintana but none with Staphylococcus epidermidis.

Macroepidemiology of the HIVs-AIDS (HAIDS) pandemic. Insufficiently considered zoological and geopolitical aspects

The human immunodeficiency viruses (HIVs)-acquired immunodeficiency syndrome (AIDS) or HAIDS pandemic originated from lentiviruses of nonhuman primates (thus qualifying as a zoonosis) that moved into humans in Africa. The HAIDS patients eventually die of opportunistic infections, all potentially zoonotic. The HAIDS infection remained parochial, first endemically and then epidemically, until the African urbanization that occurred in each of the countries postindependence. The latter included wars and the massive movement of soldiers (virologically naive) from the American continent to Africa and back. The HAIDS viral ecology coincided with African swine fever (ASF) in the Americas. Haiti became the focal point for both infections. Some infected Haitians also became, together with some infected drug addicts in the United States, a source of contaminated human blood for transfusions and production of plasma derivatives.

Characterization of a novel Rochalimaea species, R. henselae sp. nov., isolated from blood of a febrile, human immunodeficiency virus-positive patient

Isolation of a Rochalimaea-like organism from a febrile patient infected with human immunodeficiency virus was confirmed. Analysis of 16S rRNA gene sequences, together with polymerase chain reaction and restriction endonuclease length polymorphism analysis of a portion of the citrate synthase gene, demonstrated that the agent is closely related to members of the genus Rochalimaea and that the isolate is genotypically identical to the presumptive etiologic agent of bacillary angiomatosis. However, the same genotypic analyses readily differentiated the new isolate from isolates of other recognized Rochalimaea species as well as other genera of bacteria previously suggested as putative etiologic agents of bacillary angiomatosis and related syndromes. We propose that the novel species be referred to as Rochalimaea henselae sp. now.

Rochalimaea henselae sp. nov., a cause of septicemia, bacillary angiomatosis, and parenchymal bacillary peliosis

Nine strains of Rochalimaea spp. that were isolated from patients over a period of 4.5 years were characterized for their enzyme activities, cellular fatty acid compositions, and DNA interrelatedness among Rochalimaea spp., Bartonella bacilliformis, and Afipia felis (cat scratch disease bacillus). All except one isolate, which was Rochalimaea quintana, were determined to belong to a newly proposed species, Rochalimaea henselae sp. nov. After recovery from clinical material, colonies required 5 to 15 days of incubation to become apparent. Cells were small, gram-negative, curved bacilli and displayed twitching motility. Enzyme specificities for amino acid and carbohydrate substrates showed that R. henselae could be distinguished from Rochalimaea vinsonii by L-arginyl-L-arginine and L-lysyl-L-alanine peptidases, but not all strains could be distinguished from R. quintana on the basis of peptidases or carbohydrate utilization. R. henselae also closely resembled R. quintana in cellular fatty acid composition, with both consisting mainly of C18:1, C18:0, and C16:0 fatty acids. However, the strains of R. henselae all contained C18:0 in amounts averaging greater than or equal to 22%, in contrast to R. quintana, which contained this cellular fatty acid in amounts averaging 16 and 18%. DNA hybridization confirmed the identification of one clinical isolate as R. quintana and showed a close interrelatedness (92 to 100%) among the other strains. Under optimal conditions for DNA reassociation, R. henselae showed approximately 70% relatedness to R. quintana and approximately 60% relatedness to R. vinsonii. Relatedness with DNA from B. baciliformis was 43%. R. henselae was unrelated to A. felis. R. henselae is the proposed species of a newly recognized member of the family Rickettsiaceae, which is a pathogen that may be encountered in immunocompromised or immunocompetent patients. Prolonged fever with bacteremia or vascular proliferative lesions are clinical manifestations of the agent.

Clinical, histologic, microbiologic, and biochemical characterization of the causative agent of bacillary (epithelioid) angiomatosis: a rickettsial illness with features of bartonellosis

It has been suggested that bacillary (epithelioid) angiomatosis (BEA) is a manifestation of cat scratch disease (CSD). Because of clinical similarity between this condition and the verruga peruana phase of bartonellosis, we sought to further characterize this disease as well as its causative agent and to compare it to bartonellosis. We isolated a small flagellated pleomorphic bacillus from skin lesions of two patients with BEA. Organisms were stained successfully with Warthin-Starry silver stains, but immunohistochemistry failed to demonstrate binding with a polyclonal antibody directed against the cat scratch bacillus. Whole cell fatty-acid gas chromatography performed on both BEA organisms and Bartonella bacilliformis demonstrated marked similarity between the two. Electron microscopy of BEA organisms in tissue and in suspension revealed features characteristic of a gram negative bacillus. Based on these findings, we propose that this unusual rickettsial infectious disease with vascular proliferation may represent an unusual variant of infection with a bartonella-like organism rather than a manifestation of cat scratch disease.

The agent of bacillary angiomatosis. An approach to the identification of uncultured pathogens

BACKGROUND

Bacillary angiomatosis is an infectious disease causing proliferation of small blood vessels in the skin and visceral organs of patients with human immunodeficiency virus infection and other immunocompromised hosts. The agent is often visualized in tissue sections of lesions with Warthin-Starry staining, but the bacillus has not been successfully cultured or identified. This bacillus may also cause cat scratch disease.

METHODS

In attempting to identify this organism, we used the polymerase chain reaction. We used oligonucleotide primers complementary to the 16S ribosomal RNA genes of eubacteria to amplify 16S ribosomal gene fragments directly from tissue samples of bacillary angiomatosis. The DNA sequence of these fragments was determined and analyzed for phylogenetic relatedness to other known organisms. Normal tissues were studied in parallel.

RESULTS

Tissue from three unrelated patients with bacillary angiomatosis yielded a unique 16S gene sequence. A sequence obtained from a fourth patient with bacillary angiomatosis differed from the sequence found in the other three patients at only 4 of 241 base positions. No related 16S gene fragment was detected in the normal tissues. These 16S sequences associated with bacillary angiomatosis belong to a previously uncharacterized microorganism, most closely related to Rochalimaea quintana.

CONCLUSIONS

The cause of bacillary angiomatosis is a previously uncharacterized rickettsia-like organism, closely related to R. quintana. This method for the identification of an uncultured pathogen may be applicable to other infectious diseases of unknown cause.

Clinical and pathological features of bacillary peliosis hepatis in association with human immunodeficiency virus infection

BACKGROUND

Peliosis hepatis is characterized by cystic, blood-filled spaces in the liver and is seen in patients with chronic infections or advanced cancer and as a consequence of therapy with anabolic steroids. Cutaneous bacillary angiomatosis is a bacterial infection that occurs in patients with human immunodeficiency virus (HIV) infection; its histologic appearance is that of a pseudoneoplastic vascular proliferation.

METHODS

We studied liver tissue from eight HIV-infected patients with peliosis hepatis, two of whom also had cutaneous bacillary angiomatosis. For comparison we examined tissue from four patients who had peliosis hepatis without HIV infection. Tissues were examined histologically on routine sections and with special stains and electron microscopy.

RESULTS

The histologic features seen in peliosis hepatis associated with HIV infection, but not in the four cases unrelated to HIV infection, were myxoid stroma and clumps of a granular purple material that on Warthin-Starry staining and electron microscopy proved to be bacilli. The bacilli, which could not be cultured, were morphologically identical to those found in the skin lesions of cutaneous bacillary angiomatosis. The clinical courses of two of the patients with this "bacillary peliosis hepatis" indicate that it responds to antibiotic treatment.

CONCLUSIONS

HIV-associated bacillary peliosis hepatis is an unusual, treatable opportunistic infection, probably caused by the same organism that causes cutaneous bacillary angiomatosis. Our failure to find bacilli in non-HIV-associated cases implies that other pathogenetic mechanisms may also be responsible for peliosis hepatis.

Visceral bacillary epithelioid angiomatosis: possible manifestations of disseminated cat scratch disease in the immunocompromised host: a report of two cases

Opportunistic infection with the causative agent of cat scratch disease may be responsible for an unusual vascular proliferative lesion, referred to as bacillary epithelioid angiomatosis, previously described only in human immunodeficiency virus (HIV)-infected patients. We present a case of an HIV-infected patient with bacillary epithelioid angiomatosis involving the liver and bone marrow causing progressive hepatic failure. We also report a case of a cardiac transplant recipient with hepatic and splenic bacillary epithelioid angiomatosis manifesting as a fever of unknown origin, a previously unreported event in a non-HIV-infected patient. These cases represent the first documentation of bacillary epithelioid angiomatosis with visualization of cat scratch-like organisms involving internal organs.

Epithelioid angiomatosis in patients with AIDS. Report of seven cases and review of the literature

Seven cases of a distinctive vascular proliferation in patients with acquired immunodeficiency syndrome are discussed and compared with other reported cases. All cases share clinical and pathologic manifestations that can be recognized early. Warthin-Starry-positive bacilli within some of the lesions and their response to erythromycin may indicate that the proliferation is associated with an infectious agent, possibly the bacillus that causes cat-scratch disease.

Bacillary angiomatosis: a newly characterized, pseudoneoplastic, infectious, cutaneous vascular disorder

Bacillary angiomatosis (also called epithelioid angiomatosis) is a newly recognized disease most often characterized by a cutaneous infection with reddish papules of vascular origin. It is caused by a weakly reactive gram-negative bacillus, which can be easily demonstrated in tissue sections with the Warthin-Starry stain. Bacillary angiomatosis usually responds readily to treatment with oral erythromycin, 250 to 500 mg, taken four times a day for 2 weeks to 1 month. Because the skin is the most common site of involvement, it is important that the dermatologist recognize this unusual condition. It is essential that treatment be started as soon as possible because deaths may result from visceral and mucosal involvement. The clinical, histologic, and microbiologic aspects of bacillary angiomatosis are discussed and depicted in detail and speculations regarding the pathogenesis are rendered.

Cat-scratch disease: a review of the literature

Cat-scratch disease (CSD) is a common cause of chronic lymphadenopathy (especially regional) that primarily affects children and adolescents. The clinical diagnosis of CSD is based on the presence of three of four criteria, which may include a positive CSD skin test. Usually a benign, self-limiting disease, CSD may sometimes have atypical manifestations and serious complications, particularly in immunocompromised hosts. Cat-scratch disease is now known to be caused by a small, gram-negative, pleomorphic bacterium. Antibiotics are dramatically effective against CSD in immunocompromised patients, but are not [corrected] of proven benefit in typical cases. Most patients recover with only symptomatic treatment. This article reviews the history of CSD research, clinical features of typical and atypical CSD, and current topics of interest in CSD research, especially in the areas of diagnosis and treatment.

Epithelioid angiomatosis or cat scratch disease with splenic and hepatic abnormalities in AIDS: case report and review of the literature

Cat scratch disease (CSD) in the setting of HIV infection is associated with lesions of epithelioid angiomatosis but not with granulomatous lesions seen in the normal host. We report a case of CSD in a patient with AIDS and Kaposi's sarcoma with epithelioid angioma of skin, thrombocytopenia, and abnormalities of liver, spleen, lymph node, and pleura that responded to antimicrobial therapy. We also review reported cases of epithelioid angiomatosis in HIV infections. 12 of these resolved, including 3 without antimicrobial therapy; 18 demonstrated pleomorphic organisms with Warthin-Starry silver stain. Six involved visceral or bony as well as skin lesions. CSD should be considered in the setting of HIV infection with skin nodules even in the presence of biopsy-proven Kaposi's sarcoma. CSD may in these patients be responsible for a variety of disseminated lesions which respond to antimicrobial therapy.

Epithelioid angiomatosis in the acquired immunodeficiency syndrome: morphology and differential diagnosis

A rare vascular proliferation found as a skin lesion in patients suffering from the acquired immunodeficiency syndrome and sometimes referred to as epithelioid angiomatosis is believed to be a manifestation of infection by the cat scratch bacillus or a related organism. We describe the histological findings from eight lesions seen in two cases. In all cases the diagnosis could be confirmed by demonstration within the lesions of groups of gram-negative rod-shaped organisms staining positively with the Warthin-Starry stain. This condition needs to be distinguished from a variety of reactive and neoplastic vascular proliferations.

Infection-associated vascular lesions in acquired immunodeficiency syndrome patients

Several reports have recently appeared in the literature describing "unique" non-neoplastic vascular lesions in patients with the acquired immunodeficiency syndrome (AIDS). These lesions may be mistaken clinically and histologically for Kaposi's sarcoma. The terms epithelioid angiomatosis, epithelioid or histiocytoid hemangioma, and pyogenic granuloma have all been used to describe a similar entity in which cat scratch disease bacillus (CSDB) was subsequently identified. Lesions closely resembling this entity occur in patients with bartonellosis. We report a case of a cutaneous vascular lesion on the hand of an AIDS patient in which cytomegalovirus (CMV) and organisms consistent with CSDB were both found. Simultaneous infections with CMV and CSDB have not been previously described. The presence of these organisms in and around endothelial cells may provide the common stimulus for the formation of these reactive vascular proliferations.

Ultrastructural findings in clinically uninvolved oral mucosa of patients with HIV infection

Twelve biopsies of clinically normal oral mucosa taken from HIV seropositive patients have been investigated by means of light- and electron microscopy. Vascular abnormalities were found in all biopsies, regardless of the clinical stage of the HIV infection. In particular slit-like vascular channels, sparseness of intercellular junctions and swollen, protruded endothelial cells with an increased quantity of Weibel-Palade bodies were noticed. These findings were similar to those described in lesions of early stage Kaposi's sarcoma.