Metanephric adenoma vs. Wilms' tumor: a report of 2 cases with diagnosis by fine needle aspiration and cytologic comparisons.

BACKGROUND: Metanephric adenoma (MA) is a rare benign renal neoplasm that can occur at any age, whereas, Wilms' tumor (WT) is the most common malignant renal neoplasm in children and is occasionally seen in adults. CASES: In case 1, a 26-year-old male had a left renal mass. Fine needle aspiration (FNA) showed 3-dimensional sheets of cells with nuclear overlapping, molding, irregular nuclear membrane and distinct nucleoli. Frequent mitotic figures could be seen. The cytologic differential diagnosis included Wilms' tumor, neuroectodermal tumor and metanephric adenoma. Nephrectomy revealed Wilms' tumor. In case 2, a 24-year-old female presented with erythrocytosis and a right renal mass. FNA showed small, uniform cells with smooth nuclear membrane, fine chromatin and inconspicuous nucleoli. A diagnosis of metanephric adenoma was made and confirmed on nephrectomy. CONCLUSION: Differentiating MA from WT based on cytologic features on FNA biopsy prior to surgical resection can he difficult.

A proposal for a new and more practical grading scheme for pancreatic ductal adenocarcinoma.

There is no uniformly applied grading system for pancreatic ductal adenocarcinoma (DA). The scheme advocated by the WHO is essentially that of Kloppel et al, and is based on the "highest grade" focus. Although it is precise with good prognostic value, it is unfortunately not widely applied, largely because of the lack of recognition and partly because of its complex nature (interpretation of multiple parameters). Furthermore, it is fundamentally different from the one used in Japan, which evaluates the overall pattern. To establish a more widely applicable, practical, and clinically relevant grading system, a scheme similar to Gleason's scoring system was developed and tested on 112 cases of resected pancreatic DA and was compared with the WHO system. In the grading system devised, patterns (P) of infiltration were classified as follows: P1, well-defined glands with easily discernible contours; P2, fused or poorly formed glands with ill-defined contours; P3, nonglandular patterns. A score was then obtained by the summation of the predominant and the secondary patterns. Scores < or =3 (at least some well-formed glands and no nonglandular pattern) was graded as G1, 4 as G2, and > or =5 (at least some nonglandular patterns and no well-formed glandular pattern) as G3. Seventy-three percent of the cases displayed mixed patterns, with disparate patterns (P1 with P3) in 13%, confirming the high degree of heterogeneity of DA. There was a significant correlation between grade and survival, better than the correlation between survival and either the major or minor patterns evaluated separately. The median survival for G1, G2, and G3 were 22, 14, and 8 months; 1-year survival 68%, 44%, and 33%; 2-year was 67%, 11%, and 0%; and 3-year was 23%, 4%, and 0%, respectively (P = 0.0019). In a multivariate analysis, correlating survival with grade, tumor size, and lymph node status, the grade was the strongest independent predictor of survival. Odds ratio of dying of disease were 3.56 (P < 0.0001) in G3 versus G1, 1.79 (P = 0.058) in G2 versus G1, and 1.98 (P = 0.03) in G3 versus G2. Compared with this, the same odds ratio were 1.17 (P = 0.01) in tumors >2 cm versus < or =2 cm and 1.78 (P = 0.01) in cases with positive versus negative lymph nodes. The WHO grading scheme was not found to have as good a correlation with survival in this study, with WHO grade 2 showing a better survival than 1. The reproducibility of both the proposed grading system and that of WHO were found to be moderately good (with kappa values of 0.43 and 0.44, respectively), when 32 slides of DA were graded by four independent observers. The grading scheme for pancreatobiliary adenocarcinoma proposed here is highly applicable because it is practical and readily adoptable. It reflects biologic characteristics of ductal carcinoma (prominent tubule formation and tumor heterogeneity). Most importantly, it is clinically relevant with good prognostic value. Lastly, it is also applicable for use in research, by utilizing "patterns," even in small specimens like microarrays or biopsies.

Excessive Endothelial Cell Proliferation Occurring in an Organizing Thyroid Hematoma: Report of a Case and Review of the Literature.

The authors report a case of a thyroid hematoma containing an exuberant endothelial cell proliferation. No underlying vascular neoplasm was apparent and the hematoma occurred in a substernal goiter from a 90-yr-old male. Review of the literature revealed four similar previously reported cases of endothelial cell proliferation found in thyroid hematomas for a total of five cases. A fine needle aspiration or biopsy procedure antedated the definitive surgery in four patients and may be responsible for the formation of the hematoma in these cases. Areas of the endothelial proliferation resembled papillary endothelial hyperplasia (Masson's hemangioma) in four cases and cavernous hemangioma in three. However, these lesions occurred outside of vascular lumina and instead were intimately associated with fibrinous material of the hematoma. In addition, two cases contained foci of endothelial cells with nuclear atypia or intracytoplasmic lumens requiring distinction from angiosarcoma. These vigorous endothelial proliferations most likely represent alterations in the organization of a thyroid hematoma, a process similar to papillary endothelial hyperplasia, which is usually intravascular. Primary vascular neoplasms of the thyroid are exceedingly rare. Nevertheless, awareness of exuberant endothelial cell proliferation as a potential, albeit rare, manifestation of a thyroid hematoma should prompt careful attention to distinguish this reactive process from vascular neoplasms such as hemangioma or angiosarcoma.