Expression of CD30 (Ber-H2) in nasopharyngeal carcinoma, undifferentiated type and lymphoepithelioma-like carcinoma. A comparison study with anaplastic large cell lymphoma.

AIMS: Undifferentiated nasopharyngeal non-keratinizing carcinoma (UNPC), formerly known as lymphoepithelioma, frequently metastasizes at an early stage to regional lymph nodes and, thus, may be difficult to distinguish from Hodgkin's lymphoma (HL) or anaplastic large cell lymphoma (ALCL). CD30 expression is a useful diagnostic stain in both HL and ALCL, but its expression in UNPC deserves clarification. The aim of this study was to evaluate CD30 expression in UNPC and lymphoepithelioma-like carcinoma (LELC) from other anatomic locations and compare it with ALCL and squamous cell carcinoma (SCC). METHODS AND RESULTS: CD30 immunoreactivity was examined in 38 cases of primary or metastatic UNPC, six cases of LELC, 10 cases of SCC and seven cases of ALCL. CD30 immunoreactivity was observed in four of 38 (10.5%) cases of UNPC. CD30 staining was absent in all cases of LELC (0/6) and SCC (0/10). All cases of ALCL (7/7) were strongly positive for CD30. CONCLUSIONS: The majority of cases of UNPC are immunohistochemically negative for CD30; however, a small subset of cases expresses CD30 antigen. These findings provide additional evidence that CD30 expression is not restricted to neoplasms of lymphoid origin. This should be taken into consideration when interpreting CD30 immunohistology and the possibility of UNPC.

Increased incidence of atypical Papanicolaou tests from ThinPreps of postmenopausal women receiving hormone replacement therapy.

BACKGROUND: The authors noticed a significant increase in the rate of atypical squamous cells of undetermined significance (ASCUS) diagnoses in postmenopausal women receiving hormone replacement therapy with ThinPrep (monolayer) Papanicolaou (Pap) tests (8.3%) as compared with conventional Pap tests (2.3%; P = 0.025). The purpose of this study was to correlate these morphologic changes with human papillomavirus (HPV) DNA detection by in situ hybridization and clinical outcome. METHODS: Twenty-five monolayer Pap tests diagnosed as ASCUS in postmenopausal women receiving hormone replacement, as well as 2 cases of low-grade squamous intraepithelial lesion (SIL) from the same group, were destained in acid alcohol. In situ HPV hybridization was performed with a consensus probe that can detect greater than 90% of the HPV types that occur in cervical SIL. In addition, 11 of the ASCUS tests were analyzed with the periodic acid-Schiff (PAS) stain. RESULTS: All 25 ASCUS tests were negative for HPV DNA as compared with a detection rate of 15 of 17(88%) for low-grade SIL. Glycogen that was PAS positive was present in the atypical squamous cells of the postmenopausal women for whom HPV was not detected. Clinical follow-up demonstrated that only 2 of the 25 women with ASCUS had a subsequent biopsy proven SIL. CONCLUSIONS: The ThinPrep preparation can produce artifactual HPV-like changes in postmenopausal women receiving hormone replacement therapy that may be caused by glycogenization and, because of the high incidence of HPV negativity and negative clinical outcome, are best considered as benign cellular changes.

Cystic synovial sarcoma.

A case of synovial sarcoma of the paraspinal region showing massive cystic changes is described. The tumor presented in a 53-year-old white woman who noticed a lump on the upper aspect of her back. Magnetic resonance imaging of the cervical spine showed a heterogeneous paraspinal mass with well-defined margins and a multilocular quality with foci of hemorrhage. Fine needle aspiration of the mass showed clusters of polygonal cells admixed with a scattered spindle cell component. Surgical excision of the mass showed a well-circumscribed but nonencapsulated tumor that showed multiple small cystic structures on cross-section. Histologic examination showed a biphasic neoplasm characterized by bland-appearing glandular elements embedded in a moderately cellular spindle cell stroma. The tumor contained multiple cysts of varying size. Immunohistochemical studies showed the glandular component to be positive for cytokeratin and epithelial membrane antigen. The spindle cell component was immunoreactive for cytokeratin, vimentin, bcl-2, and CD99. Stains for muscle-specific actin, smooth muscle actin, S-100 protein, and CD34 were negative. Cytogenetic analysis showed a balanced reciprocal translocation involving chromosomes X and 18, in addition to other clonal abnormalities. Synovial sarcoma should be considered in the differential diagnosis of cystic lesions involving the soft tissues. Magnetic resonance imaging is considered the procedure of choice for the evaluation of soft tissue tumors because of its superior soft tissue contrast and multiplanar imaging capability. While the imaging features of soft tissue tumors are often nonspecific, magnetic resonance imaging may provide helpful clues, thus narrowing the differential diagnosis. Immunohistochemical studies and cytogenetic analysis may be very helpful for establishing the correct diagnosis in cases with this unusual presentation. Ann Diagn Pathol 5:48-56, 2001.

Soft tissue aspiration cytopathology.

BACKGROUND: Fine-needle aspiration (FNA) biopsy as a diagnostic modality for the pathologic evaluation of soft tissue neoplasms and non-neoplastic soft tissue mass lesions is uncommon and controversial. This procedure contrasts with more traditional diagnostic methods such as marginal excision, incisional (open) biopsy, or even core biopsy to procure tissue from somatic sites. METHODS: The authors reviewed the results of cytopathologic diagnoses obtained by fine-needle aspiration biopsy over a consecutive 11-month period in patients that presented primarily with a palpable soft tissue mass. A few patients with deep non-palpable soft tissue masses also were evaluated by radiologically guided FNA. Cytopathologic diagnoses were verified by different means including tissue examination either by concurrent cell block or subsequent surgical biopsy, flow cytometry, clinical outcome, or repetition of the FNA procedure. Patients were followed for a minimum of one year to evaluate the mass clinically, to determine whether any further therapy was administered, and to assess disease status. RESULTS: Eighty-two aspirates were performed without complications from 77 patients ranging from 12-88 years of age (mean = 50 yrs.) with men outnumbering women 1.5:1. Soft tissue masses were most common in the extremities (41 cases), followed by the trunk (34 cases), retroperitoneum (5 cases), and head and neck (2 cases). Fine-needle aspirates were diagnosed as malignant in 42 (51%), benign in 32 (39%), nondiagnostic in 6 (7%), and atypical in 2 (2%) cases. Malignant aspirates were comprised of 24 sarcomas (57%), 9 carcinomas (21%), 6 malignant lymphomas (14%), and 3 melanomas (7%). Twenty-two aspirates (52%) had an initial diagnosis of malignancy, whereas 18 (43%) represented metastatic and 2 (5%) recurrent neoplasms. Confirmation of the cytopathologic diagnosis was by concurrent or subsequent tissue examination in 57%, flow cytometry in 5%, clinical outcome in 34%, and repeat aspiration in 4%. One false negative and no false positive diagnoses were issued for a sensitivity and specificity of 100% and 97% respectively in distinguishing benign and malignant lesions by FNA. Of the malignant aspirates, 83% could be subtyped whereas 72% of benign aspirates were correctly subtyped. For primary soft tissue sarcomas, 12 of 19 (63%) were accurately subtyped. In 48% of cases a concurrent cell block was obtained and found diagnostically useful in 54% of them. CONCLUSIONS: Aspiration cytopathology of soft tissue mass lesions using FNA biopsy can be an accurate and minimally invasive method for the initial pathologic diagnosis of primary benign and malignant soft tissue masses, for the pathologic confirmation of metastatic tumors to soft tissue, and for the documentation of locally recurrent soft tissue neoplasms. FNA cytopathology is capable of specifically subtyping a large percentage of primary and metastatic soft tissue tumors if cellular material either in the form of a cell block or flow cytometry is obtained in addition to cell smears.

Aspiration cytopathology of epithelioid angiosarcoma.

BACKGROUND: Epithelioid angiosarcoma (EA) is an uncommon neoplasm readily mistaken for carcinoma. In contrast to the histopathology of this tumor, the cytopathology as obtained using fine-needle aspiration (FNA) biopsy has rarely been described. METHODS: Three patients with histologically and immunohistochemically proven EA each underwent FNA using standard technique before surgical resection. RESULTS: Aspirate smears were obtained from 3 males (ages 47, 63, and 15 years) each of whom presented with a solitary palpable soft tissue mass, 1 from the left calf and 2 from the right popliteal region. No patient had a history of malignancy or had been exposed to prior radiation therapy. Smears were relatively hypocellular due to the dilutional effects of abundant blood. Cells were scattered on slides primarily in a single cell dissociated pattern; small aggregates were present in a fraction of the slides. Malignant cells generally monotonous in size and averaging three to four times the dimension of a mature lymphocyte had a rounded so-called epithelioid configuration. Cells possessed primarily rounded, single nuclei often eccentrically placed, with some anisokaryosis, and smooth nuclear borders. Binucleated cells with mirror-image nuclei were much less frequent, and cells with three or four nuclei were even more scarce. Cells contained large single nucleoli or more often multiple misshapen smaller nucleoli. Cytoplasm was abundant and finely granular in virtually all cells. In some, the cytoplasm acquired a central spheric density thus producing a "rhabdoid" appearance that was only seen with air-dried Diff-Quik (Fisher Scientific, Biochemical Sciences, Inc., Swedesboro, NJ) stained smears. Mitoses were readily found. Immunostaining of the cell block in one case permitted a specific diagnosis of EA before subsequent surgical excision. CONCLUSIONS: Epithelioid angiosarcoma may display a rhabdoid morphology in FNA biopsy smears, and this cytopathology can closely mimic that of nonsmall carcinoma, malignant melanoma, and other epithelioid types of soft tissue tumors. Immunophenotyping is essential for definitive diagnosis. Cancer (Cancer Cytopathol)

Fine-needle aspiration cytopathology in diagnosis and classification of malignant lymphoma: accurate and reliable?

Diagnosis of malignant lymphoma by fine-needle aspiration biopsy (FNAB) remains a topic of skepticism and controversy. Because of the limitations of pure morphology, subclassfication of non-Hodgkin malignant lymphoma (NHML) by FNAB often requires ancillary studies which impose a challenge not typically required of other FNAB diagnoses. Despite the dubiousness expressed by many, the evidence shows that a large percentage of NHML cases can be recognized and correctly classified using FNAB. Diagnostic accuracy is dependent on several factors including the type of NHML. The emergent WHO classification of lymphomas is one that appears to more readily accommodate the cytologic methods for NHML diagnosis.

Myxomatous soft tissue tumors: correlation of cytopathology and histopathology.

A small, uncommon group of soft tissue tumors are distinguished by their unique and consistent ability to produce an overwhelming abundance of myxoid ground substance along with the proliferating cells that constitute the tumor. Grossly, all these neoplasms have a variable gelatinous quality. Because of the voluminous stroma, most of these tumors have some findings that overlap with one another. Nonetheless, each tumor has a composite set of morphologic, immunophenotypic, ultrastructural, and genotypic features exclusive to itself. Because soft tissue masses are not a frequent site of fine-needle aspiration, the cytopathology of this set of tumors is vastly unappreciated, both in the literature and in day-to-day practice. The aim of this review is to detail the salient light microscopic findings of this group of six major myxoid soft tissue tumors, to correlate the cytopathology (particularly as obtained using the fine-needle aspiration biopsy technique) with its histopathologic counterparts, and to discuss the limitations of both cytologic and histologic methods. This cytohistopathologic correlation should assist the reader in the diagnosis of myxoid tumors of soft tissue.

Intragraft cytokine expression in tolerant rat renal allografts with rapamycin and cyclosporin immunosuppression.

The Th-1/Th-2 paradigm proposes clonal expansion of Th-2 lymphocytes as the basis of tolerance towards allografts. Intragraft cytokine expression was evaluated in a highly stringent model of renal transplantation. ACI and Lewis rats were used as donors and recipients, respectively, for heterotopic renal transplantation. Group A (n = 8) received a single dose of rapamycin and cyclosporin 12 h prior to engraftment, followed by 7 d of cyclosporin post-operatively. Isografts (Group B, n = 5) and control allografts (Group C, n = 4) received no immunosuppression. Sacrifice was performed after 120 d. Intragraft expression of IL-10, IL-4, and IFN-gamma was determined using qualitative reverse transcriptase-polymerase chain reaction (RT-PCR). All groups had functionally normal grafts at sacrifice, with 50% histological tolerance among Group A animals. No isografts showed evidence of cellular infiltrate, and all control allografts showed severe rejection. IL-10 was only detected in the tolerant animals (p < 0.001). Similarly, IL-4 was detected predominantly in the tolerant allografts (p < 0.05). IFN-gamma was only isolated in rejected allografts, whether treated or untreated (p < 0.001). We conclude that the expansion of Th-2 cells is associated with tolerance, while the expansion of Th-1 cell is associated with acute cellular rejection.

Fine needle aspiration cytopathology of malignant lymphoma.

Morphologic features allowing the cytopathologist to distinguish a reactive lymph node from a malignant lymphoproliferative disorder and to distinguish Hodgkin lymphoma from non-Hodgkin lymphoma are presented in concert with pertinent immunophenotypic profiles of various lymphomas. The limitations and diagnostic pitfalls of aspiration cytopathology in the diagnosis of lymphoma and lymphoid aspirates are also discussed.

Flow cytometric analysis of chimerism in the rat tolerant to a renal allograft.

BACKGROUND: Chimerism, produced by the two-way migration of cells between graft and host, is a proposed mechanism by which tolerance occurs. The appearance of donor/recipient chimeras in tolerant ACI to Lewis rat heterotopic renal transplants was assessed in peripheral blood leukocytes using flow cytometry after staining with monoclonal antibodies. MATERIALS AND METHODS: ACI and Lewis rats were used as donor and recipient, respectively, after Rapamycin and Cyclosporin immunosuppression with or without donor blood or bone marrow transfusion. ACI and Lewis animals were also used for isograft and single-kidney controls. Animals were sacrificed at various time points after initial operation. Flow cytometry was performed on isolated peripheral blood leukocytes at sacrifice. Histologic and functional data were also obtained. The monoclonal antibody panel included RT1(a) (ACI, MHC I) combined with CD2, CD4, CD8, CD16, and CD25 or RT1(a,c) (bone marrow chimeras). RESULTS: RT1(a)+, CD8+ cells were transiently present in the peripheral blood leukocytes of Lewis recipients with the exception of allogeneic bone marrow recipients. No significant number of RT1(a)+, CD16+ ("dendritic" cell-line) chimeras was seen. Veto cells (RT1(a,c)+) were transiently present in the bone marrow recipients, but they did not lead to improved outcome. Furthermore, no correlation was made between histologic tolerance and any of these donor-derived cells. CONCLUSION: Donor/recipient chimerism, and the veto cell phenomenon are not operational tolerance mechanisms in this stringent model of ACI to Lewis rat renal transplantation.

The immunologic role of IFN-gamma in ACI to Lewis kidney transplantation.

BACKGROUND: One of the proposed mechanisms of tolerance induction is the Th-1/Th-2 paradigm. The Th-1 cell is proinflammatory, secreting IFN-gamma and IL-2. Conversely, the Th-2 cell is anti-inflammatory, secreting IL-4 and IL-10. In our earlier studies a shift toward Th-2 dominance was required for tolerance induction in this model. MATERIALS AND METHODS: ACI and Lewis rats were used as donors and recipients, respectively. Twelve hours prior to engraftment, rapamycin 1.5 mg/kg po and cyclosporin 10 mg/kg sc were given, followed by 5 mg/kg sc postop (days 1-7). Lewis rats were used as isografts. Functional allograft tolerance was induced consistently in 100% of the recipients with 50% of the allografts exhibiting normal histology beyond 120 days. Qualitative RT-PCR was performed on the grafts to determine IFN-gamma expression with beta-actin housekeeping gene as control. RESULTS: IFN-gamma was expressed in all untreated allografts (5/5) and all treated, yet rejecting, allografts (4/4). None of the isografts (0/5) or histologically tolerant allografts (0/4) expressed IFN-gamma. This distribution was statistically significant (P < 0.001, Fischer's exact test). CONCLUSION: Our findings support a shift from Th-2 to Th-1 predominance as the corollary mechanism responsible for preventing histologic tolerance.

The cytopathology of synovial sarcoma: a study of six cases, with emphasis on architecture and histopathologic correlation.

BACKGROUND: In this article, the architectural and cytologic features of synovial sarcoma are described. METHODS: Romanowsky- and Papanicolaou-stained fine-needle aspiration smears and corresponding hematoxylin and eosin sections were retrieved from archival material and examined by light microscopy. RESULTS: Microtissue fragments comprised of spindle cells dominated smears and correlated with fibrosarcoma-like areas prevalent in tissue sections. Characteristic fascicular and whorled patterns were apparent, and matrix material representing collagenous stroma varied from fibrillary to hyalinized. Epithelial components included polygonal and rectangular cells isolated from spindle cells, gland-like formations occurring within otherwise spindle cell microtissue fragments, and clubbed, spindle cell collections lined by flattened epithelial cells. CONCLUSIONS: Features of synovial sarcoma as defined previously by histopathology were apparent in cytologic preparations, facilitating a primary diagnosis by cytology.

Fine-needle aspiration cytopathology of malignant fibrous histiocytoma.

BACKGROUND: Most pathologists generally accept malignant fibrous histiocytoma (MFH) as the most common soft tissue sarcoma in adults. This study examines the authors' aspiration cytopathology experience with this tumor, describes its cytomorphology, and determines the reliability of such a diagnosis by fine-needle aspiration biopsy (FNAB). METHODS: The authors' files were reviewed for cases diagnosed as MFH by FNAB, and for surgical pathology cases of MFH previously aspirated but not diagnosed as such by cytology. RESULTS: Fifty-two cases of MFH (by FNAB or histology) were recovered from the combined files; 42 aspirates had tissue confirmation. Patient age ranged from 15-88 years (mean, 63 years); the male:female ratio was 1.2. Thirty aspirates were from primary tumors, and 12 were from recurrences or metastases. From the 29 aspirates diagnosed as MFH, 24 (83%) were determined to be MFH on subsequent surgical excision. Four of the remaining cases were other sarcoma subtypes, and there was one organizing thrombus (false-positive). The remaining 13 aspirates were identified as unqualified sarcoma (11 cases) or a different sarcoma subtype (2 cases). Eleven of these were histologically diagnosed as MFH, and 2 as other sarcomas. No single cytologic feature or combination of features distinguished MFH. Patterns ranged from single cells to large storiform fragments. Spindled, plasmacytoid, and pleomorphic cell shapes were found; pleomorphic cells were often multinucleated. All cases of MFH had malignant nuclear morphology. Diagnostic pitfalls included low cellularity, obscuring blood and inflammation, and inadequate clinical and/or radiologic information. CONCLUSIONS: The diagnostic role of FNAB in soft tissue lesions remains controversial. FNAB is important in the initial triage of patients with soft tissue tumors, and is particularly accurate for confirming recurrent or metastatic disease. Although making an initial diagnosis of sarcoma by FNAB is reliable, specific subtyping of them as MFH is more problematic.

Fibromatosis colli. The utility of fine-needle aspiration in diagnosis.

BACKGROUND: Fibromatosis colli (FC), also known as sternocleidomastoid tumor of infancy, is a benign spindle cell lesion of the sternocleidomastoid muscle. It usually is seen in the first few weeks of life and is the most common cause of a neck mass in the perinatal period. Although FC may lead to congenital muscular torticollis requiring surgical intervention, if the diagnosis of FC is certain, the usual initial treatment option is conservative management. OBJECTIVE: To show the utility of fine-needle aspiration in the diagnosis of FC. PATIENTS: Five cases in which fine-needle aspiration was used in the evaluation of patients with FC were identified retrospectively by a search of the cytopathology files of the State University of New York Health Science Center at Syracuse and the Virginia Commonwealth University, Medical College of Virginia, Richmond. RESULTS: Fine-needle aspiration yielded an initial diagnosis of FC in 4 of the 5 cases. Smears made from the aspirated material were of low cellularity, but showed a characteristic population of spindle-cell fibroblasts. In addition to these fibroblasts, a variable amount of degenerating skeletal muscle was present in the background. CONCLUSION: With the collaborative efforts of otolaryngologists and pathologists, fine-needle aspiration can be used to confirm a clinical diagnosis of FC while avoiding the expense and risk of open biopsy.

Analysis of functional renal allograft tolerance with single-dose rapamycin based induction immunosuppression.

The induction of transplantation tolerance is one of the primary goals following solid organ transplantation. The combination of a single dose of rapamycin (RAPA) with a short course of cyclosporine (CsA) has been shown to induce transplantation tolerance in the nonfunctional rat heterotopic cardiac transplant model. The purpose of this study was to assess this effective induction protocol in a functional renal transplant model. Male ACI (RTl(a)) and Lewis (RT1(1)) rats were used as donor and recipients respectively. Allografts received a single RAPA dose of (1.5 mg/kg) combined with CsA (10 mg/kg) 12-14 hr prior to transplantation. CsA (5 mg/kg) was given daily on days +1 - +7. Untreated Lewis to Lewis isografts served as histological controls. Chimerism, assessed in recipient skin, and intragraft interleukin (IL) 10 expression was determined utilizing PCR and RT-PCR techniques respectively. Treated animals and isografts were sacrificed 120-130 days posttransplant for functional and histological evaluation. Allografts (n=9) were functionally tolerant with serum creatinine (0.77+/-0.1 vs. 0.88+/-0.1; P=0.275), blood urea nitrogen (37.6+/-4.6 vs. 23.3+/-1.9; P=0.123), and 24 hr protein excretion (27.0+/-4.4 vs. 17.9+/-5.2; P=0.131) similar to single kidney ACI controls. Histologically, 45% (4/9) allografts were indistinguishable from isografts with no evidence of rejection, and were considered immunologically tolerant. Donor/recipient chimerism was not detected. All immunologically tolerant allografts had evidence of intragraft IL-10 expression. Rejecting allografts and isografts did not express intragraft IL-10. This study confirms the efficacy of pre-engraftment single-dose RAPA combined with CsA in inducing true immunologic tolerance in this stringent functional renal transplant model. The expression of intragraft IL-10 in tolerant recipients suggests a Th-2 shift as the mechanism of tolerance in this model.

Aspiration and imprint cytopathology of salivary duct carcinoma.

BACKGROUND: Salivary duct carcinoma (SDC) is a highly malignant primary epithelial neoplasm of the salivary glands. The histology of this lesion resembles that of cribriform and comedo-type intraductal carcinoma of the breast, yet the cytopathology of salivary duct carcinoma has been described in only a few instances in the past. METHODS: The authors report two cases of SDC diagnosed by fine-needle aspiration biopsy and one case imprinted after resection. The cytologic features that may permit diagnosis of this entity are described. RESULTS: Cytologic features include variably cellular smears containing loose clusters of cribriform and glandlike aggregates; monomorphic polygonal cells with round-to-oval nuclei; abundant, finely granular cytoplasm; indistinct nucleoli; and variable necrosis. CONCLUSIONS: The cytologic findings for SDC are relatively unique and may allow for its specific diagnosis on aspiration cytopathology.

Touch imprints in the intraoperative diagnosis of anterior mediastinal neoplasms.

OBJECTIVE: To evaluate the accuracy of intraoperative diagnosis of mediastinal lesions using touch imprints and frozen sections. DESIGN: We studied touch imprints and frozen sections from 21 anterior mediastinal lesions retrospectively. The lesions included six cases of non-Hodgkin's lymphoma, eight thymomas, two thymic carcinomas, three Hodgkin's disease cases, and two seminomas. Slides were reviewed independently by each of the three authors, and diagnoses were recorded. RESULTS: Depending on the observer, the correct diagnosis was obtained on touch imprints alone in 76% to 81% of cases. On frozen sections alone, the correct diagnosis was made in 67% to 86% of cases. In 86% to 100% of cases, the correct diagnosis was made on either touch imprint or frozen section. CONCLUSIONS: As with frozen sections, the most common significant error in interpreting cytology preparations was in distinguishing thymic epithelial tumors (thymoma and thymic carcinoma) from lymphoma. On a modified Wright-Giemsa-stained imprint, epithelial cells in a thymoma may be inconspicuous. Clues to their presence include cells with a spindled nuclear shape or a small distinct nucleolus. The epithelial cells have scant cytoplasm with indistinct cell borders. Clumping of cells is often not prominent in lymphocytic thymomas, but may be present in epithelial or mixed lymphocytic and epithelial tumors. With practice, one can learn to recognize thymic epithelial cells on touch imprints. Familiarity with this simple inexpensive technique could improve the accuracy of intraoperative diagnosis of anterior mediastinal lesions.

Cytologic features of necrotizing granulomatous inflammation consistent with cat-scratch disease.

Approximately 2,000 cases of cat-scratch disease are reported annually. It is an uncommon cause of unilateral lymphadenopathy in children and adults. We present the cytologic features of necrotizing granulomatous lesions consistent with cat-scratch disease from various sites. Eleven cases from 10 patients with a mean age of 16 yr (range, 2-33 yr) were biopsied by fine-needle aspiration. All gave a history of previous exposure to cats. Two children had atypical presentations; one with multiple hypodense areas within the liver and spleen, and the other with features of encephalitis. Other locations included lymph nodes from axilla, inguinal, preauricular, and cervical areas, and other body sites such as the scapula and the parotid gland. Histologic staging of the inflammatory process was correlated with cytologic features. There were 5 cases of early features, 3 cases in the middle phase, and 3 cases in late stage. The differential diagnosis of each stage is discussed. The 2 children with atypical presentations are described in detail.