Benjamin A. Wood

Imaging of Breast Cancer With Optical Coherence Tomography Needle Probes: Feasibility and Initial Results

Optical coherence tomography (OCT) is a high-resolution imaging modality with the potential to provide in situ assessment to distinguish normal from cancerous tissue. However, limited image penetration depth has restricted its utility. This paper demonstrates the feasibility of an OCT needle probe to perform interstitial imaging deep below the tissue surface. The side-facing needle probe comprises miniaturized focusing optics consisting of no-core and GRIN fiber encased within either a 22- or 23-gauge needle. 3-D OCT volumetric data sets were acquired by rotating and retracting the probe during imaging. We present the first published image of a human breast cancer tumor margin, and of human axillary lymph nodes acquired with an OCT needle probe. Through accurate correlation with the histological gold standard, OCT is shown to enable a clear delineation of tumor boundary from surrounding adipose tissue, and identification of microarchitectural features.

Parametric imaging of the local attenuation coefficient in human axillary lymph nodes assessed using optical coherence tomography

We report the use of optical coherence tomography (OCT) to determine spatially localized optical attenuation coefficients of human axillary lymph nodes and their use to generate parametric images of lymphoid tissue. 3D-OCT images were obtained from excised lymph nodes and optical attenuation coefficients were extracted assuming a single scattering model of OCT. We present the measured attenuation coefficients for several tissue regions in benign and reactive lymph nodes, as identified by histopathology. We show parametric images of the measured attenuation coefficients as well as segmented images of tissue type based on thresholding of the attenuation coefficient values. Comparison to histology demonstrates the enhancement of contrast in parametric images relative to OCT images. This enhancement is a step towards the use of OCT for in situ assessment of lymph nodes.

Diagnosis of extramammary malignancy metastatic to the breast by fine needle biopsy

Aims: To review and illustrate the findings in fine needle biopsy (FNB) of extramammary malignancies presenting with breast metastases (MMB). Methods: We reviewed 32 cases of MMB diagnosed on breast FNB. The clinical data, with particular attention to the history of a known primary malignancy, previous systemic metastatic disease in other sites and presentation with extramammary disease in addition to a breast mass were examined. The morphological appearances were reviewed and are illustrated, focusing on those features which allow the pathologist to recognise the possibility of metastatic disease and undertake appropriate steps to investigate this. Results: The 32 cases included metastases from a wide range of sites, including cutaneous melanoma (10), lung (8), non‐Hodgkins lymphoma (5), soft tissue (4), colon (2), endometrium, ovary and bladder. There was a history of extramammary malignancy in 26, while in six patients the breast mass was detected at initial presentation with malignant disease. Of the latter six patients, four had evidence of widespread metastases, while one presented with multiple breast masses. In 16 cases the cytological features allowed the possibility of metastases to be recognised without clinical data, while in the other 16 there was sufficient overlap with primary mammary carcinoma that the possibility of metastases could be missed. Only one case was initially mistaken for a primary tumour, in this case the history of prior malignancy with systemic metastases was not provided to the reporting pathologist. Conclusion: The majority (81%) of cases of MMB have a history of primary malignancy, although only a minority have a history of systemic metastases at other sites. Of those patients without known prior malignancy, the majority present with systemic disease or multiple breast lesions. The cytological features allow metastatic disease to be suspected in half of the cases, although in the others, particularly patients with metastatic adenocarcinoma, diagnosis without recourse to immunohistochemistry is difficult or impossible. A combination of complete clinical history, attention to the cytological features and suspicion in cases with metastatic disease beyond the axilla should allow most cases of MMB to be suspected, and suitable material for ancillary confirmatory testing to be obtained.

Ultrasound-Guided Optical Coherence Tomography Needle Probe for the Assessment of Breast Cancer Tumor Margins

OBJECTIVE The purpose of this study was to evaluate a new imaging technique for the assessment of breast cancer tumor margins. The technique entails deployment of a high-resolution optical imaging needle under ultrasound guidance. Assessment was performed on fresh ex vivo tissue samples. CONCLUSION Use of the ultrasound-guided optical needle probe allowed in situ assessment of fresh tissue margins. The imaging findings corresponded to the histologic findings.

Use of In Situ Hybridization to Detect Human Papillomavirus in Head and Neck Squamous Cell Carcinoma Patients Without a History of Alcohol or Tobacco Use

CONTEXT Head and neck squamous cell carcinoma is commonly associated with tobacco and alcohol use. There are, however, a group of patients without a significant history of tobacco or alcohol use, and the etiology of these tumors is incompletely understood. OBJECTIVE To examine tumors in this subpopulation for association with human papillomavirus (HPV) using newly available in situ hybridization probes. DESIGN Between October 2004 and October 2005, 22 patients who did not use alcohol or tobacco were included. Formalin-fixed, paraffin-embedded tissue sections were used to perform in situ hybridization using newly available probe sets (Ventana Medical Systems, Tucson, Ariz). The slides were examined for the presence of integrated HPV using light microscopy. Positive and negative xenograft controls were run with the assay. Results.-The mean age of the patients was 64 years. There were 14 men and 8 women. The most common anatomic sites included tongue (n = 8), tonsil (n = 7), and larynx (n = 7). All cases and controls were successfully stained. Only 2 cases were positive for high-risk HPV, and both demonstrated an integrated pattern. Both cases were tumors of the tonsil. No cases were positive for low-risk HPV. CONCLUSIONS These results demonstrate that the new probe sets for HPV can be used very efficiently in clinical pathology material of head and neck squamous cell carcinoma. Our data show that high-risk HPV is an uncommon finding in head and neck squamous cell carcinoma from patients who do not have a history of tobacco or alcohol use; low-risk HPV was not seen in any case.

Immunohistochemical staining for p16 is a useful adjunctive test in the diagnosis of Bowen’s disease

Aims: The aim of this study was to document the pattern of immunohistochemical staining seen with p16 (INK4a) in actinic keratosis, Bowens disease and seborrhoeic keratosis. Methods: We gathered 20 examples each of actinic keratosis, Bowens disease and seborrheic keratosis. The cases were stained for p16 using standard immunohistochemical techniques, and the staining patterns were categorised into one of five different patterns. Results: All cases of Bowens disease as defined in our practice showed strong positive staining in all abnormal cells, and 95% of these cases showed a distinctive pattern of sparing in a layer of palisaded basal cells. None of the actinic keratoses or seborrheic keratoses, as defined by our morphological criteria, showed this distinctive pattern. Conclusions: Bowens disease, as we define the term, shows a distinctive, repeatable pattern of staining with p16, characterised by moderate to strong staining of all abnormal cells with sparing of a layer of basal cells. This pattern is not seen in actinic keratoses or in seborrheic keratoses. Thus immunohistochemistry for p16 is a useful adjunctive test in the differential diagnosis of these lesions.

Interobserver variability in the diagnosis of circumscribed sebaceous neoplasms of the skin

Aims: Separation of sebaceous adenoma, sebaceoma and well differentiated sebaceous carcinoma is a clinically important distinction which relies on a number of subjective criteria. In routine practice we had noted significant interobserver variability in the classification of these lesions. This study sought to determine the degree of interobserver variability between general surgical pathologists and dermatopathologists in the diagnosis of well differentiated cutaneous sebaceous neoplasms. Methods: We circulated 61 examples of well circumscribed cutaneous sebaceous neoplasms to nine pathologists, including dermatopathologists and general surgical pathologists who were asked to submit a diagnosis for each case. Fleiss’ kappa statistic was used for assessment of interobserver agreement. Results: We found that only seven cases (11%) had consensus agreement across all nine pathologists. Many cases had multiple diagnoses suggested, with three or more submitted diagnoses in 26 cases (43%), while 38 cases (62%) were diagnosed as sebaceous carcinoma by at least one pathologist. There was marked variability amongst the individual pathologists in the proportion of cases diagnosed as carcinoma, ranging from 5% to 57% of cases. Fleiss’ kappa statistic for all pathologists across all diagnostic categories was 0.44, amounting to only fair to moderate agreement. Conclusions: These data indicate that there is substantial interobserver variability in the diagnosis of well circumscribed sebaceous neoplasms. This was seen in both the separation of benign and malignant lesions, as well as in the classification of the benign entities. This interobserver variability is likely to have significant clinical implications in terms of potential for over- or under-treatment, as well as in selection of cases for mismatch repair protein evaluation.

Cutaneous basal cell carcinosarcomas: evidence of clonality and recurrent chromosomal losses

Cutaneous carcinosarcomas are heterogeneous group of tumors composed of malignant epithelial and mesenchymal components. Although mutation analyses have identified clonal changes between these morphologically disparate components in some subtypes of cutaneous carcinosarcoma, few cases have been analyzed thus far. To our knowledge, copy number variations (CNVs) and copy-neutral loss of heterozygosity (CN-LOH) have not been investigated in cutaneous carcinosarcomas. We analyzed 4 carcinosarcomas with basal cell carcinoma and osteosarcomatous components for CNVs/CN-LOH by comparative genomic hybridization/single-nucleotide polymorphism array, TP53 hot spot mutations by polymerase chain reaction and Sanger sequencing, and TP53 genomic rearrangements by fluorescence in situ hybridization. All tumors displayed multiple CNV/CN-LOH events (median, 7.5 per tumor). Three of 4 tumors displayed similar CNV/CN-LOH patterns between the epithelial and mesenchymal components within each tumor, supporting a common clonal origin. Recurrent changes included allelic loss at 9p21 (CDKN2A), 9q (PTCH1), and 17p (TP53). Allelic losses of chromosome 16 including CDH1 (E-cadherin) were present in 2 tumors and were restricted to the sarcomatous component. TP53 mutation analysis revealed an R248L mutation in both epithelial and mesenchymal components of 1 tumor. No TP53 rearrangements were identified. Our findings indicate that basal cell carcinosarcomas harbor CNV/CN-LOH changes similar to conventional basal cell carcinoma, with additional changes including recurrent 9p21 losses and a relatively high burden of copy number changes. In addition, most cutaneous carcinosarcomas show evidence of clonality between epithelial and mesenchymal components.

Desmoplastic melanoma: Recent advances and persisting challenges

Summary Desmoplastic melanoma is an uncommon variant of melanoma which presents significant challenges to the clinician and histopathologist. In particular, many cases show a bland ‘fibroblastic’ appearance, mimicking scar and a range of other benign proliferations. This diagnosis can be particularly problematic in small biopsy specimens, a difficulty exacerbated by an immunoprofile which is typically negative for a number of conventional melanocytic markers. The clinical and histological features of desmoplastic melanoma are reviewed, as are the differential diagnoses and some newer techniques which may contribute to assessment of these lesions. In recent years it has become clear that subclassification of desmoplastic melanoma into pure and mixed variants has clinical significance and it is suggested that this classification be employed in routine practice.

Practical issues concerning the implementation of Ki-67 proliferative index measurement in breast cancer reporting

Summary Commercial molecular tests which rely heavily on proliferation markers to stratify breast cancer are in increasing demand, but are expensive and not widely available. There is heightened interest in the use of Ki-67 immunohistochemistry as a marker of proliferation. This study sought to examine practical issues in the incorporation of Ki-67 measurement into breast cancer reporting. We conducted a prospective study of Ki-67 proliferative activity in 85 breast carcinomas in 70 patients. We considered whether dual staining with cytokeratin and Ki-67 was necessary to exclude background cells in automated digital image analysis (DIA) and how well a semi-quantitative assessment (SQA) method of Ki-67 proliferation and formal manual counting by two pathologists correlated with DIA. Our study showed good correlation between single and dual stained specimens by DIA (Spearman correlation coefficient 0.8), with a kappa statistic of 0.51 (moderate agreement) but with significantly fewer positive cells identified in dual stained sections. There was fair correlation between SQA and DIA by two pathologists (Spearman correlation coefficient 0.7 and 0.7). Using a ≥10% cut-off to define cases with a ‘low’ and ‘high’ proliferative index gave a kappa statistic of 0.25 and 0.32 (fair agreement). There was fair correlation between formal manual counts between two pathologists (Spearman correlation coefficient 0.7; kappa 0.32). Repeat DIA on all cases showed excellent correlation (Spearman coefficient 0.98; kappa 1.0). Automated digital analysis of Ki-67 PI is likely to be more accurate and consistent than semi-quantitative assessment and more practicable than formal manual counting. There remain challenges in standardisation of technique within and across laboratories, interpretation of results and in evaluating clinical relevance.