Anatomic Abstracts

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May 2002

Clinicopathologic correlates of solitary fibrous tumors
Solitary fibrous tumors are rare neoplasms arising from the pleura but subsequently reported from a variety of extrathoracic sites. The authors conducted a study to compare thoracic and extrathoracic SFTs with regard to behavior. They studied 79 patients treated at Memorial Sloan-Kettering Cancer Center during an 18-year period. Thirty-seven percent of the cases studied were thoracic and the remainder represented a variety of locations, including various pelvic and abdominal sites. The authors noted that, overall, SFTs had a low rate of local recurrence and metastasis after surgical treatment, although extrathoracic SFTs were more likely to recur. Positive surgical margins and the presence of a histologically malignant component were factors predicting worse local recurrence-free survival, while positive surgical margins, tumor size greater than 10 cm, and the presence of a malignant component predicted a worse metastasis-free survival rate.

Gold JS, Antonescu CR, Hajdu C, et al. Clinicopathologic correlates of solitary fibrous tumors. Cancer. 2002;94:1057-1068.

Reprints: Dr. Daniel G. Coit, Dept. of Surgery, Memorial Sloan-Kettering Cancer Center, 1275 York Ave., New York, NY 10021; coitd@mskcc.org

Unusual patterns of basal cell hyperplasia of the prostate
Uncommon morphologic patterns of basal cell hyperplasia may be confused with high-grade prostatic intraepithelial neoplasia or carcinoma. The authors identified 25 cases of basal cell proliferations with unusual histologic features in a search of 559 cases diagnosed as basal cell hyperplasia. Among the 19 cases included from consultation material, 13 of 19 were sent to rule out a diagnosis of prostatic (three) or basaloid (one) carcinoma or HGPIN (four) or to classify the lesion (five). The unusual histologic features of BCH were intracytoplasmic hyaline and eosinophilic globules (five), extracellular and well-circumscribed small- or medium-sized psammomatous calcifications within glandular lumina (eight), nonkeratinizing squamous metaplasia (three), and a cribriform pattern (nine). Mixed patterns were also noted. The cribriform pattern included foci where the BCH glands had a back-to-back rather than a true cribriform architecture and appeared as a pseudoinfiltrative lesion in three of nine cases. Prominent nucleoli or cytologic atypia, or both, were noted in five cases. The authors prefer to use the term "BCH with prominent nucleoli" rather than "atypical BCH" since an adverse outcome from these lesions has not been demonstrated in the literature. Immunostaining with antibodies to high-molecular weight cytokeratin was useful in identifying the basal cell nature of the process. A continuous layer of immunoreactivity distinguished BCH from the interrupted pattern of HGPIN. BCH, unlike basaloid carcinoma, had a well-circumscribed pattern, absence of necrosis, and lack of a desmoplastic stroma. Intracytoplasmic hylaine globules may help in identifying a lesion as BCH since it has not been reported in other prostatic lesions.

Rioux-Leclercq NC, Epstein JI. Unusual morphologic patterns of basal cell hyperplasia of the prostate. Am J Surg Pathol. 2002;26:237-243.

Reprints: Dr. Jonathan I. Epstein, Johns Hopkins Hospital, Dept. of Pathology, Weinberg Building, 401 N. Broadway, Rm. 2242, Baltimore,

MD 21231; jepstein@jhmi.edu

Circumferential margin involvement important in rectal carcinoma
Despite improved surgical treatment strategies for rectal cancer, five to 15 percent of patients develop local recurrences. After conservative surgery, circumferential resection margin involvement is a strong predictor of local recurrence. The consequences of a positive CRM after total mesorectal excision have not been evaluated in a large patient population. The authors conducted a nationwide randomized multicenter trial in the Netherlands to compare preoperative radiotherapy and TME versus TME alone for rectal cancer. CRM involvement was determined according to trial protocol. The authors analyzed the criteria by which the CRM needs to be assessed to predict local recurrence for nonirradiated patients (n=656; median followup, 35 months). CRM involvement is a strong predictor for local recurrence after TME. A margin of 2 mm or less is associated with a local recurrence risk of 16 percent, compared with 5.8 percent in patients with more mesorectal tissue surrounding the tumor (P<0.0001). Furthermore, patients with margins of 1 mm or less have an increased risk for distant metastases (37.6 percent versus 12.7 percent; P<0.0001) as well as a shorter survival rate. The prognostic value of CRM involvement is independent of TNM classification. Accurately determining CRM in rectal cancer is important for determining local recurrence risk, which might subsequently be prevented by additional therapy. In contrast to earlier findings, this study showed increased risk with margins of 2 mm or less.

Nagtegaal ID, Marijnen CAM, Kranenbarg EK, et al. Circumferential margin involvement is still an important predictor of local recurrence in rectal carcinoma. Am J Surg Pathol. 2002;26:350-357.

Reprints: Dr. Iris D. Nagtegaal, University Medical Center St. Radboud, Dept. of Pathology, P.O. Box 9101, 6500 HB Nijmegen, Netherlands; I.nagtegaal@pathol.azn.nl

Features of stereotactic core breast biopsies that predict invasion in DCIS
Stereotactic incisional core breast biopsy (SCBB) is a highly specific technique for diagnosing ductal carcinoma in situ (DCIS) in patients with suspicious mammographic microcalcifications. Its sensitivity for excluding the presence of co-existing occult invasive carcinoma, however, has not been fully established. The authors correlated SCBB findings with subsequent lumpectomy/mastectomy results in 122 cases of DCIS. In 29 cases, the SCBB showed microscopic invasion (15) or was suspicious for invasion (14). In 13 percent of cases in which the SCBB showed only DCIS, invasion was identified in the subsequent resected specimens. These findings were significantly correlated with DCIS grade (low 0/26, intermediate 2/31, and high 10/36; P<.001). Also significant were the size of the DCIS field (P=.01) and the number of ducts involved by DCIS (P=.03), with 15 being the cut-off number of ducts. Overall, 50 percent of the cases suspicious for invasion showed invasion on the resected specimen, and 73 percent of those that showed definite invasion in the biopsy showed this feature in the resected specimen. The invasive tumors were generally T1b-c. The authors concluded that patients having high-grade DCIS and areas suspicious for or positive for microinvasion have a high likelihood of harboring occult invasive mammary carcinoma. Occult invasion was also correlated with the overall extent of DCIS.

Bonnett M, Wallis T, Rossmann M, et al. Histologic and radiographic analysis of ductal carcinoma in situ diagnosed using stereotactic incisional core breast biopsy. Mod Pathol. 2002;15:95-101.

Reprints: Dr. Daniel Visscher, Mayo Clinic, Dept. of Pathology, 200 First St., SW, Rochester, MN 55905; visscher.daniel@mayo.edu

Use of static image-based telepathology
Various types of technology are available to transfer image-rich pathology data between remote locations for the purposes of diagnosis, education, and research. Static image-based systems are the most widely used of these technologies. Field selection and image quality, however, are major impediments to using static images for diagnostic telepathology. Between November 1994 and July 1999, the Armed Forces Institute of Pathology performed electronic consultation on more than 1,250 static image-based cases, recording a clinically significant concordance rate of 97.3 percent between telepathology and final diagnosis in cases for which followup material was available. For the same subset of cases, the AFIP attained an absolute concordance rate of 73.7 percent. The AFIPconcluded that when all involved parties understand its limitations—the requirements for careful field selection and image interpretation and the frequent need to evaluate followup material for definitive diagnosis—static imaging can greatly benefit expert consultation.

Williams BH, Mullick FG, Butler DR, et al. Clinical evaluation of an international static image-based telepathology service. Hum Pathol. 2001;32:1309-1317.

Reprints: Bruce H. Williams, Dept. of Telemedicine, Room 3001, Armed Forces Institute of Pathology, 14th St. and Alaska Ave., NW, Washington, DC 20306-6000