Geoffrey F Watson

Sydney Cancer Centre, Camperdown, New South Wales, Australia

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Publications (6)19.8 Total impact

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    ABSTRACT: Fine-needle biopsy (FNB) is commonly used in the investigation of patients with a history of melanoma who present with possible metastatic disease. Non-melanoma malignancies (NMM) are common in the general population and not infrequent in patients with melanoma. Such tumors may be difficult to distinguish from metastatic melanoma on FNB. We sought to determine the types of NMMs that occur in melanoma patients, to document the frequency with which they were diagnosed by FNB, and to highlight potential pitfalls in cytologic diagnosis. NMMs occurring in 1416 consecutive melanoma patients who underwent FNB of 2204 clinically suspicious lesions between 1992 and 2002 at a single center were reviewed and analyzed. The sites of FNB included lymph nodes (36.9%), skin and subcutis (25.1%), visceral locations (17.9%), and other sites (20.0%). Of the 1416 melanoma patients investigated by FNB, 116 (8.2%) had a metachronous or synchronous NMM; the NMM was diagnosed by the FNB in 17 (14.7%) patients. The most common NMMs were epithelial tumors (69.4%, most commonly carcinomas of large bowel, breast and prostate) and hematologic malignancies (21.8%). As NMMs are not infrequent in patients with melanoma, they should always be considered in the differential diagnosis of clinically suspicious masses in patients with a history of melanoma, as well as in patients at high risk of melanoma. Careful assessment of the FNB cytologic features and directed use of ancillary studies should enable accurate diagnosis in most cases and facilitate appropriate patient management.
    Melanoma research 03/2010; 20(3):203-11. · 2.06 Impact Factor
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    ABSTRACT: Transitional cell metaplasia (TCM) of the cervix and vaginal vault is rarely reported. We sought to describe the clinical and cytological features and cytological differential diagnosis of TCM. Cervical and vaginal vault smears reported as TCM or smears from patients with histologically confirmed TCM were examined for the following features: cellularity, architecture, background cell population, cell group thickness, cell shape, nuclear features (shape, chromatin, nucleoli, outline), perinuclear haloes, the presence in cell groups of a surface layer of cuboidal cells, and associated pathology. The cases of TCM were compared with smears of conventional atrophy and high grade squamous intraepithelial lesion (HSIL). Six cases (five cervical, one vaginal vault) of TCM were identified from six patients (age range 34-80 years, median 60 years). The smears showed three-dimensional cell groups (2-5 cells in thickness) composed of oval-shaped cells with small amounts of cytoplasm and spindle/oval-shaped nuclei, with the impression of 'streaming' in some groups. The nuclei showed mild membrane irregularities, evenly distributed chromatin, and small nucleoli. Nuclear grooves were identified in at least occasional cells in four cases. A surface layer of cuboidal cells was identified in two cases. The background contained dysplastic squamous cells in three cases. Atrophic changes were present and in one case some cell groups exhibited transition from TCM at one end to more conventional atrophic parabasal cells at the other. Awareness of the cytological features of TCM is critical to avoid a false-positive diagnosis of HSIL, and the consequent ramifications for patients. TCM should always be considered in the differential diagnosis of multilayered cell groups in cervicovaginal smears, particularly in peri- and post-menopausal women and in atrophic conditions.
    Pathology 02/2010; 42(2):113-8. · 2.66 Impact Factor
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    ABSTRACT: Desmoplastic melanoma (DM) is a rare subtype of melanoma characterized by malignant spindle cells associated with prominent fibrocollagenous stroma. Primary melanomas may be entirely desmoplastic ("pure" DM) or exhibit a desmoplastic component admixed with a nondesmoplastic component ("combined" DM). The cytologic features of only 5 cases of DM have been reported previously. Fine-needle biopsy (FNB) specimens from 20 recurrent or metastatic lesions in patients with cutaneous DM and 20 recurrent or metastatic lesions from patients with primary cutaneous non-DM were examined and compared. FNB specimens of patients with DM were less cellular (P = .009) and less often exhibited intranuclear cytoplasmic invaginations (P = .008) and mitotic figures (P = .006) than specimens from patients with non-DM. "Combined" DMs were more commonly composed of epithelioid cells (P = .017) and less often contained bizarre/giant tumor cells (P = .010) than did "pure" DMs. Recurrent and metastatic DM has a range of cytologic appearances. Awareness of the cytologic features and careful clinicopathologic correlation will assist in accurate FNB diagnosis.
    American Journal of Clinical Pathology 12/2008; 130(5):715-23. · 2.88 Impact Factor
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    ABSTRACT: The use of fine needle biopsy (FNB) for the diagnosis of metastatic melanoma can lead to the early removal and treatment of metastases, reduce the frequency of unnecessary surgery, and facilitate the staging of patients enrolled in clinical trials of adjuvant therapies. In this study, the accuracy of FNB for the diagnosis of metastatic melanoma was investigated. A retrospective cohort study was performed with 2204 consecutive FNBs performed on 1416 patients known or suspected to have metastatic melanoma. Almost three-quarters (1582) of these FNBs were verified by either histopathologic diagnosis following surgical resection or clinical follow-up. FNB for metastatic melanoma was found to have an overall sensitivity of 92.1% and a specificity of 99.2%, with 69 false-negative and 5 false-positive findings identified. The sensitivity of the procedure was found to be influenced by six factors. The use of immunostains, reporting of the specimen by a cytopathologist who had reported >500 cases, lesions located in the skin and subcutis, and patients with ulcerated primary melanomas were factors associated with a significant improvement in the sensitivity of the test. However, FNBs performed in masses located in lymph nodes of the axilla and FNBs that required more than one needle pass to obtain a sample were far more likely to result in false-negative results. FNB is a rapid, accurate, and clinically useful technique for the assessment of disease status in patients with suspected metastatic melanoma.
    Annals of Surgical Oncology 01/2008; 15(1):323-32. · 4.12 Impact Factor
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    ABSTRACT: Fine-needle biopsy (FNB) has been reported as a rapid, minimally invasive technique for the diagnosis of metastatic melanoma. The diagnostic accuracy of FNB was assessed in a consecutive series of 2,204 FNBs of clinically suspicious lesions from patients with previous primary melanomas treated at the Sydney Melanoma Unit, Sydney, Australia, between January 1992 and December 2002. The sensitivity and specificity of FNB were 96.3% and 98.9%, respectively. There were 5 false-positive cases (0.6%), which were verified as metastatic adenocarcinoma (3 cases) or reactive processes (organizing hematoma and chronic osteomyelitis, 1 each). False-negative diagnoses (6.7% of cases) were associated with a variety of clinicopathologic factors, including difficult-to-access anatomic sites (eg, high axilla or deep inguinal), small lesions, and lesional characteristics such asfibrosis, necrosis, or cystic change. FNB is a highly accurate, rapid, and cost-effective procedure for the diagnosis of metastatic melanoma and should be considered as the initial diagnostic procedure of choice in patients with melanoma with clinically suspected metastases.
    American Journal of Clinical Pathology 04/2007; 127(3):385-97. · 2.88 Impact Factor
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    ABSTRACT: The current study was performed to determine whether tumor mitotic rate (TMR) is a useful, independent prognostic factor in patients with localized cutaneous melanoma. From the Sydney Melanoma Unit database, 3661 patients with complete clinical information and details of primary tumor thickness, ulcerative state, and TMR were studied. TMR was expressed as mitoses per mm(2) in the dermal part of the tumor in which most mitoses were seen, as recommended in the 1982 revision of the 1972 Sydney classification of malignant melanoma. To determine which was the more prognostically useful method of grouping TMR, two separate methods (A and B) were used. Factors predicting melanoma-specific survival were analyzed using the Cox proportional hazards regression model. Patients with a TMR of 0 mitoses/mm(2) had a significantly better survival than those with 1 mitosis/mm(2) (P < 0.0001) but no significant survival differences were recorded for the stepwise increases from 1-2, 2-3, 3-4, and 4-5/mm(2). Tumor thickness, ulceration, and TMR were closely correlated, whether TMR was grouped using Method A (0, 1-4, 5-10, and >/= 11 mitoses/mm(2)) or Method B (0-1, 2-4, and >/= 5 mitoses/mm(2)). However, Cox regression analysis indicated that the TMR was a highly significant independent prognostic factor, particularly when grouped according to Method A, in which it was second only to tumor thickness as the most powerful predictor of survival (P < 0.0001). TMR is an important independent predictor of survival for melanoma patients. If confirmed by studies from other centers, it has the potential to further improve the accuracy of melanoma staging, as well as to define more rigidly the risk categories for patients entering clinical trials.
    Cancer 03/2003; 97(6):1488-98. · 5.20 Impact Factor