Alexandra N. Kalof

D2-40 Immunohistochemistry—so Far!

D2-40 is a commercially available monoclonal antibody directed against human podoplanin, a transmembrane mucoprotein that is expressed in lymphatic endothelial cells. Since its introduction, D2-40 immunoexpression has been described in a variety of lymphovascular neoplasms including lymphangioma, Kaposi sarcoma, and hemangioendothelioma, as well as nonvascular neoplasms such as epithelioid mesothelioma, seminoma, and hemangioblastoma. More recently, D2-40 immunoexpression has been reported in primary adrenal cortical tumors, schwannomas, and adnexal tumors of the skin. This brief review provides an update on the everexpanding proposed applications of D2-40 immunohistochemistry in surgical pathology.

p16INK4a immunoexpression: surrogate marker of high-risk HPV and high-grade cervical intraepithelial neoplasia.

p16INK4a has emerged as a valuable surrogate marker for high-risk human papillomavirus infection and shows increased immunoexpression with worsening grades of cervical intraepithelial neoplasia (CIN). Numerous studies have emerged in recent years supporting its role in the detection of high-grade dysplasia and have lead to the use of p16INK4a immunohistochemistry in many laboratories. However, only a few studies have examined the possible predictive or prognostic value of p16INK4a in CIN or cervical cancer. This review addresses some of the practical issues in the application of p16INK4a in everyday practice, with an emphasis on integrating the extensive data that have emerged in the literature on p16INK4a immunoreactivity in CIN. The potential role of p16INK4a immunohistochemistry in the prediction of CIN progression is also discussed.

p16INK4A immunoexpression and HPV in situ hybridization signal patterns: potential markers of high-grade cervical intraepithelial neoplasia.

Integration of human papillomavirus (HPV) into the cell genome is considered to be an important event in the progression of cervical neoplasia. p16INK4a, also a useful biomarker of cervical intraepithelial neoplasia (CIN), shows increased immunoexpression with worsening grades of CIN. This study examines the correlation between p16INK4a immunoexpression, grade of CIN, HPV type, and HPV in situ hybridization diffuse and punctate signal patterns (linked to episomal and integrated viral particles, respectively) in 44 cervical biopsies/LEEP excisions classified as CIN 1 and CIN 2/3. In 22 of 25 (88%) CIN 1 lesions, p16INK4a immunoexpression was confined to the lower half of the epithelium, with sporadic to focal staining in 11 of 25 cases (44%). In CIN 2/3 lesions, 15 of 17 (88.2%) showed diffuse, two-thirds to full-thickness staining of the epithelium. High-risk HPV types were found in 20 (80%) CIN 1 lesions and 17 (100%) CIN 2/3 lesions. Punctate signals were detected in only 3 (13.6%) of high-risk HPV-positive CIN 1 lesions and in 17 of 17 (100%) CIN 2/3 lesions (P < 0.001). p16INK4a immunoexpression and the presence of punctate signal on HPV in situ hybridization correlated with the degree of cervical neoplasia (P < 0.001). However, 3 cases of CIN 1 demonstrating punctate signals did not demonstrate a comparable CIN 2/3 p16INK4a staining pattern. Similarly, two CIN 1 lesions with comparable CIN 2/3 p16INK4a staining showed no evidence of viral integration. Both increased p16INK4a immunoexpression and punctate signal correlate with CIN 2/3 grade, supporting the use of either, or both, tests to confirm CIN 2/3. Strong p16INK4a immunostaining in CIN 1 appears independent of HPV punctate signal type.

Immunostaining patterns of myoepithelial cells in breast lesions: a comparison of CD10 and smooth muscle myosin heavy chain.

Background: Recent studies have reported CD10 expression in myoepithelial cells (MEC) of the breast, supporting its use as a marker to help distinguish invasive breast carcinoma (IC) from ductal carcinoma in situ (DCIS). Aim: To compare the effectiveness of CD10 with smooth muscle myosin heavy chain (SMMHC) in the detection of MEC in benign and malignant breast lesions. Methods: Histological material from 25 patients with DCIS and 21 with IC were immunostained for CD10 and SMMHC. Staining was scored on a scale of 0 to 3+ (0, no staining; 3+, intense) and the staining distribution was documented as focal, partial, or circumferential. Results: Uniform, 3+ circumferential CD10 and SMMHC staining of MEC was seen in normal breast ducts and lobules, and in ducts and acini involved in sclerosing adenosis and apocrine metaplasia. In an analysis of total ducts involved by DCIS, 3+ circumferential staining was seen in 65 of 366 ducts (17.7%) stained for CD10 versus 190 of 396 ducts (48%) stained for SMMHC. MEC were not detected immunohistochemically in 116 of 366 ducts (31.7%) with anti-CD10 and 50 of 396 (12.7%) with anti-SMMHC. In contrast, all ICs were negative for both CD10 and SMMHC. Focal background staining of stromal myofibroblasts was seen with both CD10 and SMMHC, but CD10 showed a higher rate of non-specific staining of epithelial cells. Conclusion: Although CD10 can aid in the distinction between IC and DCIS, SMMHC is a more sensitive and specific marker of MEC and shows less heterogeneity of immunostaining patterns.

Our approach to squamous intraepithelial lesions of the uterine cervix

Morphological analysis remains the “gold standard” in the diagnosis and grading of CIN Cervical carcinoma is a significant contributor to cancer-related morbidity and mortality worldwide and the role of human papillomavirus (HPV) in the development of preinvasive and invasive cervical lesions is well established.1,2 Although significant advances have been made in elucidating the potential mechanisms of cellular transformation by HPV and in the molecular detection of HPV in cytological and surgical specimens, morphological assessment of surgical material remains the “gold standard” in the diagnosis of cervical intraepithelial neoplasia (CIN). Although management of preinvasive cervical disease depends on many factors including the age of the patient, parity and size of the lesion, clinical management often requires confirmation of CIN by histological examination with subsequent surgical treatment of high-grade lesions (CIN 2 or CIN 3). This has fueled attempts at more objective, reproducible diagnostic parameters to accurately diagnose CIN. The histological features of preinvasive cervical neoplasia (CIN 2 and 3) are well understood, however inconsistent use and misinterpretation of the morphological criteria could lead to significant intraobserver and interobserver variability.3–5 This lack of reproducibility and the fact that there are many benign changes that can mimic dysplasia of the cervical epithelium (eg, cervical atrophy and immature squamous metaplasia) have led to significant efforts to identify a surrogate marker for high-grade CIN. In the following discussion, we will present the criteria that we use in our general surgical pathology practice, along with potential pitfalls and approaches to histological mimics of cervical neoplasia. We will propose incorporating the use of ancillary techniques such as immunohistochemistry for p16INK4a and MIB-1 (Ki-67), as well as the role of HPV in situ hybridisation, in the grading of CIN. In our general surgical pathology practice at the University of Vermont, Fletcher Allen Health …

Benign fibroblastic polyp of the colorectum.

Goals: We present the clinicopathologic features, endoscopic appearance, and ultrastructure of a newly described mesenchymal polyp of the colorectum, termed benign fibroblastic polyp. Study: A total of 4 cases from our institution are analyzed using routine histopathology, immunohistochemistry, and electron microscopy, and compared with the original series of 14 cases previously described in the pathology literature. Results: Benign fibroblastic polyps appear endoscopically throughout the colorectum as submucosal lesions with a hyperplastic surface component. These lesions are histologically and ultrastructurally distinct, but overlap with other mesenchymal polyps warrants additional immunohistochemical studies for definitive classification. Conclusions: Benign fibroblastic polyps of the colorectum comprise a recently described distinct entity of mesenchymal polyps that appear to follow an indolent clinical course. Their etiology is uncertain but may be linked to an exuberant tissue response following mucosal injury. Gastroenterologists should be aware of this new entity that will be increasingly diagnosed by pathologists.

Case Report: Kaposiform Hemangioendothelioma in Multiple Spinal Levels Without Skin Changes

Kaposiform hemangioendothelioma is a rare vascular tumor of childhood that is locally aggressive but has little metastatic potential and by itself is not known to be lethal. It most commonly presents as a superficial or deep soft tissue mass with associated cutaneous lesions. Kasabach-Merritt phenomenon, a condition characterized by profound thrombocytopenia and life-threatening hemorrhage, often is associated with kaposiform hemangioendothelioma. Six cases of kaposiform hemangioendothelioma have been reported in bone, two of which were located in extracraniofacial bones. We report a diagnostically challenging case of a 6-year-old girl with kaposiform hemangioendothelioma of the thoracolumbar spine without Kasabach-Merritt phenomenon or cutaneous lesions.

Poorly Differentiated Synovial Sarcoma of the Lumbar Spine in a Fourteen-year-old Girl: A Case Report

Synovial sarcoma is a highly malignant soft-tissue tumor of mesenchymal origin that accounts for approximately 5.8% to 10% of all soft-tissue sarcomas1,2. Nearly 90% of these tumors are discovered in an extremity, with the majority involving the lower limbs1-3. Synovial sarcoma within the lumbar spine has been mentioned in only a handful of reports in the English-language literature4-9, typically as part of a case series or as the subject of study for various imaging modalities. Occurrence in the pediatric population at this location is even rarer. The purpose of the present report is to describe the case of a fourteen-year-old girl with lumbar synovial sarcoma and to document the treatment algorithm that was used. The patient was informed that data concerning the case would be submitted for publication, and she consented. A fourteen-year-old girl with no related medical history presented to her pediatrician in November 2001 with unresolved lower back pain two weeks after being struck in the lumbar region while playing soccer. Following this incident, she began experiencing paresthesias in the left lower extremity (and occasionally the right lower extremity) and on questioning was able to recall a history of mild and occasional low-back pain during the previous two months. Physical examination revealed a firm, fixed palpable mass in the lumbar paraspinal muscles, and the patient was referred for imaging studies. No neurologic examination was noted at that time. A magnetic resonance imaging scan of limited quality secondary to patient movement showed a large lesion that was located mostly in the lumbar paraspinal muscles with extension into the spinal canal at the L3-L4 level with resultant compression of the thecal sac. The patient was referred for orthopaedic consultation and was transferred to Fletcher Allen Health Care in …

Hepatic angiosarcoma five years following spontaneous intraperitoneal bleed of a hepatic mass

Primary hepatic angiosarcoma is a rare and rapidly fatal disease. We present the highly unusual identification of this lesion five years after the initial clinical presentation. In 2003, a 32-year-old man presented with abdominal pain, tachycardia, and evidence of hemorrhage. A CT scan showed a hepatic mass with intralesional hemorrhage, intraperitoneal blood, and splenomegaly. The patient was stabilized clinically. Laparoscopic core biopsies demonstrated no malignancy, only findings consistent with an old hemorrhage. Contralateral lobe biopsies revealed normal liver tissue. A metastatic workup was negative and the decision was made to observe the patient clinically with radiographic follow-up, given his suspected portal hypertension based on thrombocytopenia and splenomegaly. Sequential imaging demonstrated a decrease in the size of the mass from 12.0 cm in 2003 to 3.0 cm in 2007. Subsequent newly identified esophageal varices prompted a reevaluation of the case. A repeat biopsy demonstrated a neoplasm of vascular etiology and uncertain malignant potential. By early 2008 the lesion had increased to 4.8 cm and was resected via a left hepatic lobectomy. An extremely vascular lesion with surrounding dense fibrosis was identified and pathologic examination demonstrated a high-grade angiosarcoma. We are unaware of any previous reports suggesting such a prolonged natural history of hepatic angiosarcoma. This case may represent the possibility of malignant transformation of a lower grade vascular neoplasm such as hepatic epithelioid hemangioendothelioma to an angiosarcoma.