Anatomic Abstracts
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June 2009 Editors:
• Micropapillary variant of urothelial carcinoma in the upper urinary tract
Micropapillary urothelial carcinoma is a rare variant of urothelial carcinoma. Most studies of the disease have focused on the urinary bladder and excluded the urinary tract. Therefore, the authors analyzed the pathologic features and clinical significance of MPUC in the upper urinary tract. They searched the pathology files at their institution and identified 11 cases of MPUC of the upper urinary tract. They reviewed the histology slides and obtained clinical information by reviewing medical charts. The average age of the patients was 64.2 years (range, 22 to 76 years). The tumors were located in the renal pelvis (n=5), ureter (n=4), and ureteropelvic junction (n=2). In all cases, MPUC accounted for an average of 45 percent (range, 10 to 80 percent) of the tumor and was associated with conventional urothelial carcinoma. Lymphovascular invasion was pre-sent in all cases, and metastasis to lymph node was present in four of five patients whose lymph nodes were dissected. Two patients presented with pT2 disease, and both were alive without evidence of disease at 85 and 119 months after surgery. The other nine patients presented with pT3 or pT4 disease: four of them died of disease at an average of 18 months; four surviving patients developed distant metastases; and one surviving patient with limited followup (six months) showed no evidence of disease. The authors concluded that micropapillary urothelial carcinoma of the upper urinary tract often presents at an advanced stage with lymphovascular invasion and distant metastasis. The presence of even focal MPUC indicates a poor clinical course. Guo CC, Tamboli P, Czerniak B. Micropapillary variant of urothelial carcinoma in the upper urinary tract: a clinicopathologic study of 11 cases. Arch Pathol Lab Med. 2009;133:62–66. Correspondence: Dr. Bogdan Czerniak at bczernia@mdanderson.org
Identifying individuals with Lynch syndrome is highly beneficial. However, it is unclear whether patients should be screened using microsatellite instability (MSI) or immunohistochemistry and whether screening should target all patients with colorectal cancer or only those in high-risk subgroups. The authors conducted a study in which they performed MSI testing and immunohistochemistry for the four mismatch repair proteins of 500 tumors from unselected patients with colorectal cancer. If MSI or immunohistochemistry was abnormal, the authors performed complete mutation analysis for the mismatch repair genes. The authors found that among the 500 patients, 18 patients (3.6 percent) had Lynch syndrome. All 18 with Lynch syndrome had MSI-high tumors, and the condition was predicted correctly using immuno-histo-chemistry in 17 (94 percent) of 18 patients. Of the 18 probands, only eight patients (44 percent) were diagnosed at an age younger than 50 years, and only 13 (72 percent) met the revised Bethesda System guidelines. When these results were added to data on 1,066 previously studied patients, the entire study cohort (n=1,566) showed an overall prevalence of 44 of 1,566 patients (2.8 percent; 95 percent confidence interval, 2.1–3.8 percent) for Lynch syndrome. For each proband, on average, three additional family members carried MMR mutations. The authors concluded that one of every 35 patients with colorectal cancer has Lynch syndrome, and each has at least three relatives with the condition, all of whom can benefit from increased cancer surveillance. Immunohistochemistry is almost equally as sensitive as MSI for screening, but the former is more readily available and helps to direct gene testing. Limiting tumor analysis to patients who fulfill Bethesda criteria would fail to identify 28 percent of cases of Lynch syndrome. Hampel H, Frankel WL, Martin E, et al. Feasibility of screening for Lynch syndrome among patients with colorectal cancer. J Clin Oncol. 2008;26:5783–5788. Correspondence: Dr. Albert de la Chapelle at albert.delachapelle@osumc.edu
Lung and breast carcinomas are among the most prevalent cancers, but advances in cancer therapies can improve survival rates and be potentially curative, even for metastatic disease. Due to the high prevalence of these carcinomas, it is not unusual to encounter lung nodules in a patient with breast carcinoma. Distinguishing between primary and metastatic disease is critical for management and treatment. Neuroendocrine differentiation occasionally is present in breast carcinoma, so it is difficult to distinguish this type of cancer from pulmonary/nonpulmonary neuroendocrine tumors of the lung. The authors conducted a study to assess estrogen and progesterone receptor expression in the entire spectrum of pulmonary neuroendocrine tumors. They evaluated for estrogen and progesterone receptors 71 neuroendocrine neoplasms, including typical carcinoids (42), atypical carcinoids (seven), small-cell carcinomas (14), large-cell neuroendocrine carcinomas (two), and combined small-cell carcinomas (six). Mammary and nonsmall-cell lung carcinomas were also stained for comparison. The authors found that the entire spectrum of neuroendocrine neoplasms demonstrated focal to diffuse expression of estrogen (typical carcinoid, 23; atypical carcinoid, six; small-cell carcinoma, eight; large-cell neuroendocrine carcinoma, two; combined small-cell carcinoma, four) and progesterone (typical carcinoid, 11; atypical carcinoid, two; small-cell carcinoma, seven; large-cell neuroendocrine carcinoma, zero; combined small-cell carcinoma, two). No correlation was found between sex and estrogen/progesterone status. Estrogen and progesterone staining were also noted in endothelial cells. Mammary carcinomas expressed estrogen and progesterone more frequently than neuroendocrine carcinomas. Nonsmall-cell carcinomas had greater and similar immu-noreactivity for estrogen and progesterone, respectively. The authors concluded that although estrogen and progesterone receptor staining is frequently associated with breast and gynecologic primaries, it can also be observed in nontarget organs. Therefore, the presence of estrogen or progesterone expression, or both, in neuroendocrine tumors involving the lung should not exclude a primary pulmonary neoplasm. Sica G, Wagner PL, Altorki N, et al. Immunohistochemical expression of estrogen and progesterone receptors in primary pulmonary neuroendocrine tumors. Arch Pathol Lab Med. 2008;132:1889–1895. Correspondence: Dr. Anjali Saqi at aas177@columbia.edu
The authors conducted a study to assess infantile digital fibroma/fibromatosis (IDF) and recommend treatment options. They examined 69 such tumors from 57 pediatric patients clinicopathologically and immunohistochemically. Thirty males, 26 females, and one child of unstated gender, ranging from newborn to 120 months old (median age, 12 months), manifested 74 lesions (five identified in followup). The lesions in-volved the toe or finger (n=71) and hand or foot (n=3). Tumors ranged in size from 3 to 35 mm (median, 10 mm), and all but four patients pre-sented with a solitary lesion. Metachronous IDFs developed in seven patients within 17 to 82 months. Microscopically, the tumors showed cytologically bland fibroproliferation forming dome-shaped/polypoid nodules directly beneath the epidermis and invading the dermal adnexa. Mitotic figures ranged from zero to seven (median, one) per 20 high-powered fields. The authors identified paranuclear cytoplasmic inclusions in 57 tumors. Tumor cells immunohistochemically expressed calponin (11 of 11 tumors), desmin (nine of nine), α-smooth muscle actin (11 of 11), CD99 (11 of 11), CD117 (six of eight), heavy caldesmon (two of 11 and scattered cytoplasmic inclusions in four tumors), CD10 (one of nine), nuclear β-catenin (two of 11), and CD34 (one of 11), but not muscle actin (HUC1-1), keratins, estrogen/progesterone receptor proteins, or activated caspase-3. Twenty-eight of 38 (74 percent) patients experienced recurrent/persistent disease (single in 22 and multiple in six; median, four months after surgery). One recurrent tumor spontaneously regressed and the size of another remained unchanged for almost 17 years before reexcision. All 23 patients with followup of more than five years are currently disease free (median disease-free interval, 23 years). Minor postoperative functional or cosmetic complaints were reported in 47 percent. No patient with adequate clinical data developed digitocutaneous dysplasia syndrome or a conventional fibromatosis or relayed a family history of IDF/conventional fibromatosis. The authors concluded that IDF is a unique myofibroblastic process separable from conventional fibromatoses and histologic mimics. The authors recommend conservative excision or observation after biopsy, with additional surgery as necessary. Laskin WB, Miettinen M, Fetsch JF. Infantile digital fibroma/fibromatosis: a clinicopathologic and immunohistochemical study of 69 tumors from 57 patients with long-term follow-up. Am J Surg Pathol. 2009;33:1–13. Correspondence: Dr. William B. Laskin at wbl769@northwestern.edu
The histopathologic grade of mucoepidermoid carcinoma is an established predictor of prognosis and affects treatment protocols. Tumor behavior is more aggressive in high-grade than in low-grade mucoepidermoid carcinoma (MEC), leading to a more intensive treatment protocol. Because outcomes for patients with intermediate-grade MEC are less clear, the optimal treatment protocol for this group is not well defined. The authors investigated the treatment protocol and survival outcomes for patients treated for MEC of the head and neck. They conducted a retrospective clinical review and prospective review of histopathologic grading using the most recently established grading system for 50 patients with MEC of the head and neck from 1983 through 2004. The authors found that as histologic grade increased from low to intermediate to high, overall (P<.0001) and disease-free (P<.001) survival rates decreased significantly. These survival rates were significantly better for patients with intermediate-grade MEC than for those with high-grade disease. Overall and disease-free survival rates were similar for patients with low-grade and intermediate-grade MEC. A low rate of disease recurrence was noted in patients with intermediate-grade MEC, but this did not lead to death from disease. No patients with low-grade or intermediate-grade MEC died of the disease, but 52 percent of patients with high-grade MEC did die of the disease. Multivariate analysis revealed that histologic grade, age, and surgical margin status significantly predicted progno-sis. The authors concluded that these findings suggest that, under the current histopathologic classification system, the behavior of intermediate-grade MEC is comparable to that of low-grade MEC and different from high-grade MEC, allowing for the establishment of an evidence-based treatment protocol. Nance MA, Seethala RR, Wang Y, et al. Treatment and survival outcomes based on histolo-gic grading in patients with head and neck mu-co--epidermoid carcinoma. Cancer. 2008;113: 2082–2089. Correspondence: Dr. Stephen Y. Lai at stephenylai@gmail.com Anatomic pathology abstracts editors: Michael Cibull, MD, professor and vice chair, Department of Pathology and Laboratory Medicine, University of Kentucky College of Medicine, Lexington; Melissa Kesler, MD, and Rouzan Karabakhtsian, MD, assistant professors of pathology and laboratory medicine, University of Kentucky College of Medicine; and Megan Zhang, MD, visiting fellow, Division of Dermatopathology, University of California, San Francisco. |
