Human polyoma virus in renal allograft biopsies: morphological findings and correlation with urine cytology.

Human polyoma virus (PV) interstitial nephritis occurs in immunosuppressed patients after reactivation of latent virus in renal epithelium. Currently, there is neither general consensus about the incidence of clinically significant PV infection in renal transplants nor conclusive evidence determining its significance in the long-term graft outcome. We evaluated 601 renal transplant biopsy specimens (from 365 patients) by routine light microscopy and immunoperoxidase stains with antibody against SV40 (which cross reacts with PV). We also examined urine samples from 200 patients (100 obtained concurrently with a renal biopsy in patients presenting with acute graft dysfunction and 100 from patients with stable graft function). Electron microscopic evaluation was performed in 50 renal biopsy specimens and in 23% of all urine samples. PV was identified in 1.8% biopsy specimens (1.9% of patients). PV interstitial nephritis showed the typical viral cytopathic changes in tubular epithelial cells associated with marked tubular damage and a disproportionately mild degree of tubulitis. There was no difference in the incidence of PV in the urine of patients with acutely deteriorating versus stable renal function (18% and 19%, respectively); however, urines with large numbers of infected cells (> 10/cytospin) and inflammatory changes in the sediments corresponded invariably to patients with acute allograft dysfunction (8 of 8), and in most cases to biopsy specimens showing PV interstitial nephritis (7 of 8). Based on these findings, urine samples seem to be the most sensitive and cost-effective screening method for PV infection; only urine samples with inflamed sediments and abundant infected cells correlate with clinically significant disease. In these cases, examination of a renal biopsy is indicated. Immunohistochemical stains are useful to confirm the presence of PV but do not increase the sensitivity of diagnosis of PV if this is not already suspected on routine light microscopy. In our material, immunostains were helpful ruling out the presence of PV in a small number of biopsy specimens (2%) that showed markedly reactive tubular cells resembling PV infection. Most patients with PV interstitial nephritis responded to decreased immunosuppression; however, the decay in graft function (based on creatinine slopes) was significantly more rapid in these patients than in matched controls. Evidence of PV infection should be systematically sought in renal biopsy specimens and urine samples from renal allograft recipients.

Correlation of light microscopic, immunocytochemical and ultrastructural cytomorphology of anaplastic large cell Ki-1 lymphoma, an activated lymphocyte phenotype. A case report.

BACKGROUND: Anaplastic large cell Ki-1 lymphoma has been proposed to be a neoplasm of activated lymphocytes, mostly of T-cell origin. CASE: A previously healthy 12-year-old boy presented with a two-month history of a rapidly growing hard palate mass that involved the nasal cartilage and extended to the floor of the right orbit. By light microscopy (LM) the aspirates were very cellular, containing single, pleomorphic cells and occasional cellular aggregates. The cells showed distinct polarity, with the large, anaplastic nucleus at one end and the tapering cytoplasm, including a prominent paranuclear halo (or "hof"), at the other end ("hand mirror" appearance). The cytoplasmic border showed prominent ruffling, concentrated at the two poles of the cells and corresponding to the areas of the protopod and uropod. Immunocytochemically (ICC) the cells were positive for Ki-1, epithelial membrane antigen and UCHL-1, all of which showed both membrane positivity along with Golgi area staining. LCA showed variable membrane staining. Ultrastructurally (electron microscopy [EM]) the polarity was recapitulated, with an eccentric, horseshoe-shaped nucleus partially enclosing a prominent Golgi complex with associated centrosomes and asymmetric plasma membrane ruffling. CONCLUSION: All three levels of examination (LM, ICC and EM) revealed tumor cell features corresponding to the phenotype of the activated lymphocyte. These features are characteristic, thus allowing the diagnosis of Ki-1 anaplastic lymphoma by fine needle aspiration cytology.

Fine needle aspiration biopsy of solitary fibrous tumors. Report of two cases with histologic, immunohistochemical and ultrastructural correlation.

BACKGROUND: Although the fine needle aspiration biopsy (FNAB) technique is widely applied to thoracic and soft tissue tumors, the cytologic morphology of solitary fibrous tumors is not fully established. CASES: We report the cytologic features observed on computed tomography (CT)-guided FNAB obtained from two benign solitary fibrous tumors of the pleura in two males. The cytologic findings were compared to the light and electron microscopic features. The smears were composed of spindle cells dispersed amid a delicate network of small blood vessels. scattered among these spindle cells were also epithelioid cells arranged singly or in small clusters. These cells were polygonal, with moderately dense, homogeneous or finely vacuolated, basophilic cytoplasm and a moderately high nuclear/cytoplasmic ratio. The nuclei were oval to round and slightly hyperchromatic and rarely had small nucleoli. Abundant spindle-shaped, round, naked nuclei were seen in the background. Stains for CD34 were positive in the epithelioid and spindle cells. Histologically the lesions were composed of spindle cells embedded in a collagenous matrix. Hypercellular nodules and focal hemangiopericytic and storiform patterns were also observed. There were no features suggesting malignancy. In electron microscopic evaluation there were fibroblastic cells in a collagenous matrix as well as polygonal cells singly and in clusters with scanty to moderate amounts of cytoplasm containing sparse organelles. The cells were attached to each other by tight junctions. Occasionally, cells were surrounded by short segments of basal lamina. CONCLUSION: The cytomorphologic pattern described above correlates well with the histologic and ultrastructural findings in benign solitary fibrous tumors (SFT) and corresponds perfectly to the histogenetic concept of this lesion. As with other tumors, fine needle aspiration biopsy is helpful in the evaluation of SFT.

Diffuse alveolar damage. Morphologic features in bronchoalveolar lavage fluid.

OBJECTIVE: To evaluate the overall cytologic characteristics of diffuse alveolar damage (DAD) in bronchoalveolar lavage (BAL) specimens in search of features that could be useful in cytologic diagnosis. STUDY DESIGN: We evaluated BAL samples from patients with DAD obtained simultaneously with transbronchial biopsies (n = 8) or open lung biopsies (n = 2) or within 24 hours of autopsy (n = 2). The material was processed routinely for cytologic and histologic evaluation. RESULTS: The smears were moderately to highly cellular. All cases had large numbers of alveolar macrophages and/or desquamated alveolar cells. The epithelial component displayed various degrees of nuclear atypia. Some epithelial clusters were three-dimensional, with peripheral cells showing clear cytoplasm, protruding outwards and resembling hobnails. Other aggregates appeared two-dimensional, as sheets of cells with flattened and dense cytoplasm (squamotized). Both types of cell clusters were often associated with dense, basophilic or amphophilic, amorphous extracellular material. Counterparts of all the cytologic features were observed in the histologic material, including atypia of the alveolar lining with hobnailing, squamotization, amorphous extracellular material and hyaline membranes. CONCLUSION: The cytologic features of BAL represent a constellation of alveolar cell injury. Based on these features, DAD can be correctly diagnosed or suggested in BAL samples in the appropriate clinical setting.