p16 immunostaining in cytology specimens: its application, expression, interpretation, and challenges

INTRODUCTION

p16 immunostaining is considered as a surrogate marker for human papillomavirus (HPV)-related head and neck squamous cell carcinomas (HNSCC). Herein, the utility of p16 is evaluated in cytology specimens.

MATERIAL AND METHODS

The electronic data of a large academic institution was searched for cytology cases accompanied by p16 (2014-2018). Cases were categorized based on body sites. P16 staining was quantified (negative [0%], focal/patchy, or diffusely positive [>70%]). HPV testing was correlated where available.

RESULTS

A total of 372 cases were included (male:female, 239:133). The largest differences in application of p16 between men and women were in head/neck cases (209 versus 59) and the abdominal cases (1 versus 33), respectively. p16 diffuse staining is seen in most squamous cell carcinomas, small cell carcinomas, and gynecologic serous carcinomas. p16 expression was patchy or negative in most adenocarcinoma, neuroendocrine carcinoma, spindle cell neoplasms, and benign conditions. HPV testing was done on 217 cases including 138 cases with strong p16 (127 HPV+/11 HPV-), 20 cases with focal/patchy P16 staining (6 HPV+/14 HPV-) and 59 cases with negative p16 staining (3 HPV+/56 HPV-).

CONCLUSIONS

Diffuse p16 staining aids in the diagnosis of HPV-related carcinomas, particularly HPV-related HNSCC, across the body and according to sex. In contrast, focal/patchy p16 staining does not correlate with HPV status across various body sites. In conclusion, intensity of p16 matters and should be correlated with cytomorphology, clinical history, and ancillary studies (eg, p40 immunostaining) for an accurate diagnosis and preventing diagnostic pitfalls.

Delayed and Aberrant Presentation of VX2 Carcinoma in a Rabbit Model of Hepatic Neoplasia

A socially-housed New Zealand white rabbit presented with a large subcutaneous mass on the ventral thorax approximately 11 mo after the intrahepatic delivery of a suspension of VX2 carcinoma cells to induce hepatocellular carcinoma as part of a nanoparticle study. The mass and closely associated axillary lymph node were removed en bloc. Immunohistochemical staining identified the mass as an undifferentiated carcinoma. The rabbit demonstrated no appreciable pathology at the study end point at 16 mo after VX2 inoculation. An additional rabbit from the same VX2 injection cohort was found at necropsy to have an unanticipated intraabdominal mass, also identified as an undifferentiated carcinoma. This case report summarizes the molecular analysis of both tumors through a novel PCR assay, which identified the delayed and aberrant onset of VX2 carcinoma in an extended timeframe not previously reported.

[Clinicopathologic study of intraabdominal extranodal follicular dendritic cell sarcoma]

OBJECTIVE

To study the clinicopathologic features and immunophenotype of intraabdominal extranodal follicular dendritic cell sarcoma (FDCS) and the relationship with Epstein-Barr virus (EBV).

METHODS

The clinical and histologic features of 4 cases of FDCS were evaluated. Immunohistochemical study was performed using standard EnVision method for CD21, CD23, CD35, S-100 protein, CD68, HLA-DR, vimentin, epithelial membrane antigen, desmin, CD34 and CD117. In-situ hybridization for EBV-encoded RNA (EBER) was carried out in 2 cases.

RESULTS

The age of patients ranged from 28 to 63 years (mean=42 years). The male-to-female ratio was 3:1. The clinical presentation was abdominal discomfort, pain or mass. Radiologic examination revealed concurrent lesions in stomach and left lobe of liver in 1 patient, while non-specific intraabdominal masses were detected in the remaining cases (in which the tumor was later found to be located in the appendix, mesentery of jejunum and omentum). Two cases were misdiagnosed as gastrointestinal stromal tumor before operation. Grossly, the tumors appeared as large solid nodules, with a mean diameter of 10.8 cm. Three of the cases showed areas of necrosis. Histologically, there were plump spindle, ovoid to epithelioid cells associated with scattered multinucleated giant cells. The tumor cells were arranged mostly in storiform pattern, whorls, fascicles or solid sheets. Lymphocytic infiltrates with perivascular cuffing were noted in all cases, resulting in a distinctive biphasic pattern. Two tumors showed significant cytologic atypia, with mitotic figures (including atypical mitotic figures) readily demonstrated. The remaining case (occurring in liver) was composed of scattered large atypical cells embedded in a dense inflammatory background, mimicking inflammatory pseudotumor. Immunohistochemical study showed that all cases were positive for CD21, CD23 and vimentin. There was focal expression of CD35, S-100 protein, CD68, HLA-DR and epithelial membrane antigen. The staining for CD34 and CD117 was negative. In-situ hybridization for EBER was negative in 2 cases tested.

CONCLUSIONS

Intraabdominal extranodal FDCS is extremely rare. Familiarity with its characteristic histologic features and immunophenotype is important in distinguishing the tumor from other intraabdominal spindle cell lesions (such as gastrointestinal stromal tumor). Hepatic FDCS may show inflammatory pseudotumor-like features, resulting in misinterpretation. Non-hepatic intraabdominal FDCS seems to have little association with EBV infection.

Visceral Kaposi's sarcoma with intracranial metastasis: a rare complication of renal transplantation

The incidence of Kaposi's sarcoma (KS) has increased in solid organ transplantation recipients. This type of KS tends to be aggressive, involving lymph nodes, mucosa and visceral organs in about half of patients, sometimes in the absence of skin lesions. Brain involvement of KS has rarely been reported. A 16-yr-old Turkish boy underwent renal transplantation from his mother. The immunosuppressive regimen included prednisolone, cyclosporin A and azathioprine. Fourteen months later the azathioprine was changed to cyclophosphamide (3 mg/kg/day) because of the development of a nephrotic syndrome. After 12 weeks, the cyclophosphamide was changed to mycophenolate mofetil (MMF) to control the nephrotic syndrome. At this time his serum creatinine level rose to 2.1 mg/dL. Polyclonal or monoclonal antibodies were never given. Multiple intra-abdominal lymphadenopathy was detected on abdominal tomography at the 32nd month after renal transplantation. Kaposi's sarcoma was diagnosed via laparotomy and biopsy. He had a generalized tonic and clonic seizure and contrast enhanced cranial tomography showed two intracranial masses which had an abundant vascular component which caused a mild shift. One of the masses was removed via a burr-hole with the aim of diagnosis and treatment of the shift. A pathologic examination of the intracranial lesion was also reported as Kaposi's sarcoma. Herpes virus-8 DNA was detected by PCR in the intracranial lesion.

HIV-assocated lymphoma: a case report

We report the case of a 3(1/2) year old boy who presented with sudden onset of headache. Fever and swelling of the left eye. He had complete opthalmoplegia of the left eye and 6th cranial nerve paralysis in the right eye. He was thought to have cavenous sinus thrombosis but CT findings suggestive of lymphoma led to the correct diagnosis of HIV associated Lymphoma It view of the rising incidence of HIV infection and the protein clinical manifestations, it is advised that all patients with disseminated tumour masses should be screened for the HIV virus, and CT examination should be made available to patients.

Epstein-Barr virus association in pediatric abdominal non-Hodgkin-lymphomas from Turkey

Recent studies have shown marked geographic variation associated with Epstein-Barr virus (EBV) in pediatric Burkitt's lymphomas and Hodgkin's disease. In the present study we investigated 30 cases of pediatric extranodal high grade non-Hodgkin's lymphomas (NHL) from Turkey with an abdominal localisation. To classify them histologically and to determine the role of EBV in these lymphomas, immunohistochemistry (IHC), in situ hybridisation (ISH) and polymerase chain reaction (PCR) were used. Our series contained two histologic types: the Burkitt's or Burkitt's-like lymphomas (BL/BLL) and high grade NHL. They all were of the B cell type. The immunoglobulin heavy chain gene rearrangement revealed monoclonality in 87% of the BL/BLL cases, in contrast to the NHL cases, showing monoclonality in only 43% of the cases. EBV was found in tumor cells in a high frequency, independent of the histological subtype. EBV strains A and B were detected in 9 cases, with a preponderance of the B subtype (4/9 BL/BLL; 4/9 NHL). Our data suggest that high grade NHLs with abdominal localisation of Turkish children show the pattern of immunodeficient lymphomas to some extent.

Expression of EBV encoded nuclear small non-polyadenylated RNA (EBER) molecules in 32 cases of childhood Burkitt's lymphoma from Israel

We have analyzed paraffin sections from 32 children with histologically confirmed Burkitt's Lymphoma (BL) for the presence of EBV using in situ hybridization to detect expression of the EBV-encoded early RNAs (EBERs). EBV was present in the tumors of 11 patients (34%). Sixty nine percent of the children presented with abdominal disease, 19% had bone marrow infiltration and only one child had jaw involvement. There was no statistically significant difference between EBV positive and EBV negative children with regard to age, gender, origin, primary site at presentation, or clinical stage of disease. However, there was a trend for younger age in the children with EBV positive BL with a median age of 4, compared to 7 years in children with EBV negative BL. None of the 7 children of Ashkenazi Jewish origin had EBER positive disease. There was no difference in the treatment outcome between the EBV positive patients (estimated survival at 24 months of 82%) and EBV negative children (estimated survival rate of 71% (p=0.58)). In conclusion, although this is only a small series it seems that childhood BL in Israel has the clinical characteristics of sporadic, non-African type with 34% EBV association and a low incidence of jaw tumors. Our data suggest that Ashkenazi Jewish children with BL are less likely to have EBV positive tumors than other ethnic groups. However, more patients will need to be studied in order to assess the validity of this observation.

Recurrent Epstein-Barr virus-associated post-transplant lymphoproliferative disorder: report of a patient with histologically similar but clonally distinct metachronous abdominal and brain lesions

A liver transplant patient developed a single central nervous system (CNS) intraparenchymal lesion 5 months after the diagnosis of an intraabdominal diffuse large B-cell post-transplant lymphoproliferative disorder (PTLD). Biopsy of the new CNS lesion showed a diffuse large B-cell PTLD morphologically and immunohistochemically indistinguishable from the abdominal lesion. In addition, both lesions were positive for Epstein-Barr virus (EBV) DNA by polymerase chain reaction (PCR) and for EBV-encoded RNA by in situ hybridization. Although these results were consistent with a metastatic origin for the CNS lesion, the finding of an intraparenchymal lesion without leptomeningeal or dural spread was suggestive of a new primary CNS lymphoma. Proof that the brain lesion was a second primary and not a metastasis was obtained by immunoglobulin gene rearrangement studies and assessment of EBV clonality. Multiple primary lymphoid neoplasms arise at higher frequency in the setting of immunosuppression, and molecular investigations of tumor clonality can provide clinically relevant staging and prognostic information.

Haploid male germ cells show no susceptibility to transformation by simian virus 40 large tumour antigen in transgenic mice

Cell-type specific tumorigenesis can be induced in transgenic mice by the directed expression of simian virus 40 (SV 40) large tumour antigen (TAg). In an attempt to determine the susceptibility of haploid male germ cells to neoplastic transformation by this oncogene, transgenic mice were generated that harboured a chimeric gene composed of the SV40 T antigen genes fused to the 2.3-kb 5' flanking sequences of the rat proacrosin gene. It was previously shown that this regulatory sequence is able specifically to direct the expression of CAT reporter gene in male germ cells with the onset of translation in early haploid male germ cells. The transgene showed regulated expression in male germ cells. Although T antigen immunostaining was detected specifically in spermatids, no testicular pathology was observed. This indicates that spermatids show no susceptibility to transformation by oncogene TAg. However, in about 10% of animals of two independent transgenic lines, we could find non-testicular tumours in abdomen with a sarcoma-like structure in advanced age which showed SV40 TAg expression.

Preventive effect of IgG from EBV-seropositive donors on the development of human lympho-proliferative disease in SCID mice

The effect of weekly treatments with various gammaglobulin preparations on the development of human B-cell tumors was studied in severe combined immunodeficient (SCID) mice. SCID mice were injected i.p. with human peripheral blood mononuclear cells (PBMCs) from an Epstein-Barr virus (EBV)-seropositive healthy blood donor. Repopulated SCID mice were divided into 7 treatment groups receiving either PBS, 2 commercial gammaglobulin preparations, purified IgG prepared from pooled plasma from EBV-seronegative or -seropositive blood donors, a rabbit anti-serum against EBV envelope glycoprotein gp340 or interferon (IFN)-alpha. All treatments started 1 day after injection of PBMC and continued for 8 weeks. In the PBS-treated control group, 85% of mice developed tumors in the abdominal cavity, mostly with liver metastasis within 150 days. Tumor formation was prevented by treatment with the 2 commercial gammaglobulin preparations as well as by purified IgG from EBV-seropositive donors. In contrast, purified IgG from EBV-seronegative donors, rabbit anti-gp340 anti-serum or IFN-alpha had no effect. Our results indicate that the effect of gammaglobulin is due to the presence of specific antibodies against EBV antigens. Further experiments showed that both the time of onset and the duration of treatment, as well as the dose of Ig, are important factors for prevention of tumor formation. Studies aiming at identification of target antigens for antibodies which prevent lymphoma development may be clinically relevant for prevention and possibly treatment of lympho-proliferative disease in severely immuno-compromised patients.

Epstein-Barr virus (EBV)-associated smooth-muscle tumor arising in a post-transplant patient treated successfully for two PT-EBV-associated large-cell lymphomas. Case report

The association of Epstein-Barr virus (EBV) with smooth-muscle tumors was recently reported in the setting of acquired immunodeficiency syndrome (AIDS) and post-transplantation. We report a case of an EBV-associated smooth-muscle tumor arising in a post-transplant (PT) patient who previously was treated successfully for two EBV-associated PT large-cell lymphomas. A 4-year-old girl required cardiac transplantation for dilated cardiomyopathy when she was aged 23 months. Her PT regimen included cyclosporine, azothiaprine, and diltiazem. At 16 months PT, she presented with anemia, guaiac-positive stools, and an abdominal mass diagnosed as diffuse large-cell lymphoma of B-cell phenotype. Immunosuppressive therapy was reduced, and interferon and i.v. immunoglobulin were initiated. She rapidly developed signs of rejection, and a cardiac biopsy was performed, revealing grade IIIB rejection. Subsequently, immunosuppressive therapy increased. At 23 months PT, a biopsy was done of a large pelvic mass that was diagnosed as immunoblastic large-cell lymphoma. After treatment with chemotherapy and retinoic acid, the size of the mass markedly decreased. Follow-up computed tomography scan revealed multiple liver nodules. A needle biopsy of the liver showed a smooth-muscle tumor of indeterminate grade. Both the lymphomas and the smooth-muscle tumor contained EBV within > 95% of tumor cells by Epstein-Barr (EBER1) in situ hybridization, were of strain type A by Epstein-Barr nuclear antigen-2 (EBNA-2) polymerase chain reaction (PCR) and contained an identical 30 base-pair deletion (amino acids 346-355) of the latent membrane protein (LMP)-1 oncogene by PCR analysis. Notably, the initial large-cell lymphoma and the subsequent immunoblastic lymphoma each contained a unique p53 mutation, suggesting that they were distinct. These data suggest that the same virus contributed to the pathogenesis of both the malignant lymphomas and the smooth-muscle tumor.

Cytomegalovirus-associated stage 4S neuroblastoma relapsed stage 4

Neuroblastoma is one of the most frequent solid tumors in childhood, rarely recurrent after five years from diagnosis. Cytomegalovirus (CMV), a major pathogen causing congenital birth defects and severe opportunistic diseases, has been shown to have teratogenic, immunodepressive and oncogenic properties. The case of a girl with stage 4S neuroblastoma diagnosed at three months and relapsed as stage 4 five years later is reported. In both circumstances, active CMV infection was revealed by positive CMV-specific IgM and IgA antibodies, CMV-DNAemia and CMV culture. At three months, the patient presented with subcutaneous nodules, hepatosplenomegaly and increased aminotransferase levels, and the opsolonus-myoclonus syndrome. Mental retardation developed later on. At 5 years, relapsed neuroblastoma was preceded by a mononucleosis-like syndrome concomitant with active CMV infection and decreased levels of immune cells and natural killer activity. Clinical, virologic, and immunologic findings suggest an immune-mediated pathogenic role for CMV in this tumor.