Diagnosis of cutaneous mycobacterial spindle cell pseudotumor in the absence of typical inflammatory cells: A case report.

Mycobacterial spindle cell pseudotumor (MSP) is a non-neoplastic condition that is characterized by spindle-shaped histiocytes colonized by mycobacteria. MSP is most commonly diagnosed in the immunocompromised and, while MSP can occur throughout the body, the most common sites of MSP involvement are the lymph nodes and the skin. To diagnose MSP, histopathological analysis typically demonstrates the presence of inflammatory cells, in addition to spindle cells and the unequivocal mycobacteria, which guides the diagnosis away from potential neoplasms. If properly diagnosed and treated with appropriate antibiotic therapy, patients tend to experience almost complete resolution of their symptoms. MSP is a rare condition; to our knowledge, there have only been 11 documented cases of cutaneous MSP, including the one introduced in this report. Here, we present a unique case of a 50-year-old female on chronic immunosuppressive therapy diagnosed with cutaneous MSP in the absence of inflammatory cells on pathology.

Mycobacterium genavense-induced spindle cell pseudotumor in a pediatric hematopoietic stem cell transplant recipient: Case report and review of the literature.

We describe the first reported pediatric patient to our knowledge with a spindle cell pseudotumor caused by Mycobacterium genavense in a hematopoietic stem cell transplant recipient, and review the literature of such an entity in the transplant population.

Cellular Microbiology of Mycoplasma canis.

Mycoplasma canis can infect many mammalian hosts but is best known as a commensal or opportunistic pathogen of dogs. The unexpected presence of M. canis in brains of dogs with idiopathic meningoencephalitis prompted new in vitro studies to help fill the void of basic knowledge about the organism's candidate virulence factors, the host responses that it elicits, and its potential roles in pathogenesis. Secretion of reactive oxygen species and sialidase varied quantitatively (P < 0.01) among strains of M. canis isolated from canine brain tissue or mucosal surfaces. All strains colonized the surface of canine MDCK epithelial and DH82 histiocyte cells and murine C8-D1A astrocytes. Transit through MDCK and DH82 cells was demonstrated by gentamicin protection assays and three-dimensional immunofluorescence imaging. Strains further varied (P < 0.01) in the extents to which they influenced the secretion of tumor necrosis factor alpha (TNF-α) and the neuroendocrine regulatory peptide endothelin-1 by DH82 cells. Inoculation with M. canis also decreased major histocompatibility complex class II (MHC-II) antigen expression by DH82 cells (P < 0.01), while secretion of gamma interferon (IFN-γ), interleukin-6 (IL-6), interleukin-10 (IL-10), and complement factor H was unaffected. The basis for differences in the responses elicited by these strains was not obvious in their genome sequences. No acute cytopathic effects on any homogeneous cell line, or consistent patterns of M. canis polyvalent antigen distribution in canine meningoencephalitis case brain tissues, were apparent. Thus, while it is not likely a primary neuropathogen, M. canis has the capacity to influence meningoencephalitis through complex interactions within the multicellular and neurochemical in vivo milieu.

Unsolved matters in leprosy: a descriptive review and call for further research.

Leprosy, a chronic mycobacterial infection caused by Mycobacterium leprae, is an infectious disease that has ravaged human societies throughout millennia. This ancestral pathogen causes disfiguring cutaneous lesions, peripheral nerve injury, ostearticular deformity, limb loss and dysfunction, blindness and stigma. Despite ongoing efforts in interrupting leprosy transmission, large numbers of new cases are persistently identified in many endemic areas. Moreover, at the time of diagnosis, most newly identified cases have considerable neurologic disability. Many challenges remain in our understanding of the epidemiology of leprosy including: (a) the precise mode and route of transmission; (b) the socioeconomic, environmental, and behavioral factors that promote its transmission; and

Biochemical and pathophysiological characterization of Helicobacter pylori asparaginase.

Asparaginase was purified from Helicobacter pylori 26695 and its pathophysiological role explored. The K(m) value of asparagine was 9.75 ± 1.81 µM at pH 7.0, and the optimum pH range was broad and around a neutral pH. H. pylori asparaginase converted extracellular asparagine to aspartate. H. pylori cells were unable to take up extracellular asparagine directly. Instead, aspartate produced by the action of the asparaginase was transported into H. pylori cells, where it was partially converted to ß-alanine. Asparaginase exhibited striking cytotoxic activity against histiocytic lymphoma cell line U937 cells via asparagine deprivation. The cytotoxic activity of live H. pylori cells against U937 cells was significantly diminished by deletion of the asparaginase gene, indicating that asparaginase functions as a cytotoxic agent of the bacterium. The cytotoxic effect was negligible for gastric epithelial cell line AGS cells, suggesting that the effect differs across host cell types. An asparaginase-deficient mutant strain was significantly less capable of colonizing Mongolian gerbils. Since asparagine depletion by exogenous asparaginase has been shown to suppress lymphocyte proliferation in vivo, the present results suggest that H. pylori asparaginase may be involved in inhibition of normal lymphocyte function at the gastric niche, allowing H. pylori to evade the host immune system.

The Pathology of Lymphocytes, Histiocytes, and Immune Mechanisms in Mycobacterium tuberculosis Granulomas.

Granuloma formation is the pathologic hallmark of tuberculosis (TB). Few studies have detailed the exact production of cytokines in human granulomatous inflammation and little is known about accessory molecule expressions in tuberculous granulomas. We aimed to identify some of the components of the immune response in granulomas in HIV-positive and -negative lymph nodes. We investigated the immunohistochemical profiles of CD4+, CD8+, CD68+, Th-17, Forkhead box P3 (FOXP3) cells, accessory molecule expression (human leukocyte antigen [HLA] classes I and II), and selected cytokines (interleukins 2, 4, and 6 and interferon-γ) of various cells, in granulomas within lymph nodes from 10 HIV-negative (-) and 10 HIV-positive (+) cases. CD4+ lymphocyte numbers were retained in HIV- granulomas, whereas CD4+:CD8 + cell were reversed in HIV+ TB granulomas. CD68 stained all histiocytes. Granulomas from the HIV+ group demonstrated a significant increase in FOXP3 cells. Interleukin-2 cytoplasmic expression was similar in both groups. Interferon-gamma (IFN-γ) expression was moderately increased, IL-6 was statistically increased and IL-4 expression was marginally lower in cells from HIV- than HIV+ TB granulomas. Greater numbers of cells expressed IFN-γ and IL-6 than IL-2 and IL-4 in HIV- TB granulomas. This study highlights the varied cytokine production in HIV-positive and -negative TB granulomas and indicates the need to identify localized tissue factors that play a role in mounting an adequate immune response required to halt infection. Although TB mono-infection causes variation in cell marker expression and cytokines in granulomas, alterations in TB and HIV coinfection are greater, pointing toward evolution of microorganism synergism.

Hansen's disease with lepra reaction presenting with IgA dominant infection related glomerulonephritis.

Various renal abnormalities in leprosy have been described largely in literature but the occurrence of IgA dominant infection related glomerulonephritis in leprosy with type 2 lepra reaction has not been reported so far. We present here a 60-year-old man with a history of leprosy in the past admitted with type 2 lepra reaction, rapidly progressive glomerulonephritis with severe renal failure requiring dialysis and diagnosed to have IgA dominant infection related glomerulonephritis.

Histoid leprosy: histopathological connotations' relevance in contemporary context.

A reappraisal of histoid leprosy in the contemporary postglobal leprosy elimination era, a fallout of the World Health Organization leprosy elimination program, is succinctly outlined. The cardinal clinical expression, differential clinical diagnosis, the cytodiagnosis, and diagnostic salient histopathological features are highlighted.

Cutaneous cryptococcosis in a patient affected by chronic lymphocytic leukaemia: a case report.

Cryptococcosis is an opportunistic infection, the incidence of which is increased in the immunocompromised patients. Cryptococcus neoformans is an encapsulated fungus that mainly infects the lungs and the central nervous system, possibly involving different organs. Cutaneous cryptococcosis is classified into localized infection, usually occurring after traumatic inoculation (primary cutaneous cryptococcosis) and cutaneous manifestation due to hematogenous dissemination (secondary cutaneous cryptococcosis), mostly in patients with underlying immunosuppression. We report a case of cutaneous cryptococcosis in a patient affected by chronic lymphocytic leukaemia.

Late recurrent testicular seminoma: histological evidence is required.

INTRODUCTION: Over the past 3 decades, the appropriate management of metastatic germ cell tumours (GCT) has been defined by several phase III trials. Many follow-up recommendations have been published based on expert consensus. However, common clinical scenarios can still be vexing for clinicians who are less experienced at managing patients with testicular cancer. CASE REPORT: We highlight the arduous diagnostic work-up of a suspected late relapsing metastatic GCT in a patient suffering from fatigue, weight loss and prominent retroperitoneal lymph nodes, 4 years after first-line chemotherapy for metastatic seminoma. The various explorations finally led to the diagnosis of Whipple's disease. CONCLUSION: This unusual clinical case strongly highlights the need to perform an exhaustive evaluation, with a biopsy, if a late recurrent GCT is suspected to avoid pointless and potentially harmful treatment.

Progressive disseminated penicilliosis caused by Penicillium marneffei. Report of eight cases and differentiation of the causative organism from Histoplasma capsulatum.

Eight patients with fatal penicilliosis caused by Penicillium marneffei are reported. All were natives of southern rural Guangxi, and none had a predisposing illness or evidence of altered immunity. The distinctive features of P. marneffei include proliferation of yeast-like cells within histiocytes, followed by the development of focal necrosis and, eventually, large abscesses. Outside the histiocytes, the fungi elongate, become slightly curved, and form septa. In vitro, P. marneffei produces a red pigment which diffuses into the culture medium. The differentiation between P. marneffei and Histoplasma capsulatum is described, and possible reservoirs for P. marneffei are discussed.

Pathologic findings for bacille Calmette-Guérin infections in immunocompetent and immunocompromised patients.

The pathologic findings from biopsy specimens from 9 patients with postvaccination bacille Calmette-Guérin (BCG) infection are presented. The patients were vaccinated with BCG during the first 2 days of life. Four patients had normal immunity and 5 patients were immunocompromised. The pathologic findings in both groups were different. Biopsy specimens from patients with normal immunity showed multiple epithelioid granulomas and Langhans giant cells with or without suppuration. Caseous necrosis was minimal. Ziehl-Neelsen stain for acid-fast bacilli showed a few bacilli in 2 cases and was negative in the remaining 2 cases. Biopsy specimens from the second group of patients, who were immunosuppressed, consisted mainly of skin and subcutaneous tissue. These revealed diffuse infiltrates of histiocytes with plump nuclei and abundant "dirty" grayish cytoplasm, which was full of numerous acid-fast bacilli. The clinical course for the 2 groups also was different. Patients with normal immunity generally recover completely, spontaneously or after excision of the suppurative lymph node and usually do not require antibiotic chemotherapy. In immunosuppressed patients, disseminated BCG infection, which may prove fatal, may develop. These patients should receive a full course of antituberculous chemotherapy and, in addition, treatment of the underlying immunologic disorder.

Mycobacterial pseudotumors of lymph node. A report of two cases diagnosed at the time of intraoperative consultation using touch imprint preparations.

OBJECTIVE: The purpose of this report is to emphasize the diagnostic utility of intraoperative touch imprint preparations in the evaluation of Mycobacterium avium-intracellulare-infected lymph node biopsy specimens obtained from human immunodeficiency virus-positive patients. PATIENTS: Two human immunodeficiency virus-positive men, 41 and 29 years of age, with marked lymphadenopathy clinically suspicious for malignant neoplasm. RESULTS: Intraoperative touch imprints of two lymph node biopsy specimens rapidly demonstrated the presence of numerous intracellular organisms in Mycobacterium avium-intracellulare-infected lymph nodes, including one case of mycobacterial spindle cell pseudotumor. CONCLUSIONS: Intraoperative touch imprint preparations are helpful in the evaluation of lymph node biopsy specimens obtained from human immunodeficiency virus-positive patients and allow rapid diagnosis of Mycobacterium avium-intracellulare infection.

Neuritic Hansen's disease: an unusual presentation and a diagnostic challenge on fine-needle aspirate.

Fine-needle aspiration cytology is now routinely used in the diagnosis of cervical lumps. We report on a case of leprous neuritis which presented as a cervical swelling. A diagnosis of leprosy was suggested on the basis of globi within histiocytes. These histiocytes differed from those classically described in leprosy. Retrospective review demonstrated the presence of occasional nerve fragments, and some of these closely resembled granulomas. The possible close resemblance of this lesion to tuberculosis and a histiocytic proliferative disorder is highlighted. Recognition of nerve fragments along with histiocytes should suggest the diagnosis.

Respiratory scleroma: a clinicopathologic and ultrastructural study.

Respiratory scleroma (rhinoscleroma) is a chronic granulomatous infection produced by Klebsiella rhinoscleromatis, a gram-negative aerobic coccobacillus. This disease is endemic to Africa, Central and South America, South Central and Eastern Europe, the Middle East, and China. Sporadic cases have been reported in the United States, especially in persons who migrated from the aforementioned areas. The majority of cases affect the nose, but extension to the soft and hard palate, upper lip, and maxillary sinuses also is frequent. This study comprises 11 patients (6 females and 5 males) with respiratory scleroma identified over a 6-year period in Guatemala. Their ages ranged from 16 to 60 years. Light microscopy showed a dense plasmacytic infiltrate, Mikulicz histiocytes, and Russell bodies within the plasma cells. Ultrastructural study revealed Mikulicz histiocytes, cytoplasmic vacuoles containing bacilli, and so-called A and B granules. We favor the term respiratory scleroma for this lesion because it affects not only the nose but also the upper and lower respiratory tracts as well as the mouth.