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August 2002
False-positive results in fine-needle aspiration biopsy specimens
The authors used data from the CAP Interlaboratory Comparison Program in Nongynecologic
Cytopathology to address the rate of interpretation of normal cellular elements
as neoplastic (benign and malignant) in fine-needle aspiration biopsy specimens
from various body sites. They analyzed diagnoses made between 1998 and 2000.
False neoplastic diagnoses were rendered in 60 percent of kidney specimens,
37 percent of liver, 10 percent of pancreas, and six percent of salivary gland.
The rates are much higher than previous reports in the literature. The study
illustrates that normal cellular elements are a significant pitfall for overinterpretation
of fine-needle aspiration biopsy specimens.
Young NA, Mody DR, Davey DD. Misinterpretation of normal
cellular elements in fine-needle aspiration biopsy specimens. Arch Pathol
Lab Med. 2002;126:670-675.
Reprints: Dr. Nancy A. Young, Dept. of Pathology, Fox Chase Cancer Center, 7701 Burholme Ave., Philadelphia, PA 19111; na_young@fccc.edu
Predicting the clinical behavior of gastric stromal tumors
Gastrointestinal stromal tumors are a heterogeneous group of neoplasms that
have clinical and histologic features that vary depending on their location
within the gastrointestinal tract. It is difficult to predict clinical behavior
in this group of tumors, and the same criteria for malignancy do not necessarily
apply to stromal tumors from different sites within the gastrointestinal tract.
Using known clinical behavior with long-term followup, the authors attempted
to determine which features, if any, are associated with clinical behavior
in stromal tumors arising in the stomach, the most common site for such tumors.
Seventy-seven gastric stromal tumors were studied and classified as adverse
outcome (AO) tumors (malignant) or non-adverse outcome tumors (benign) based
on their known clinical outcome. Adverse outcome was defined as metastasis
or death due to tumor. Patients with a non-AO had at least five years of tumor/metastasis-free
followup. Thirty-seven patients had an AO (followup [metastasis at presentation]
zero to 73 months; median, six months), and 40 patients had a non-AO (followup,
60 to 264 months; median, 84 months). All cases were reviewed by two of the
authors, who were blinded to clinical outcome and gross features. The tumors
were classified as histologically benign or not benign using preset, defined
histologic criteria based on the authors' prior experience with a large number
of these tumors. If the tumor did not fit the characteristic cellular spindle
cell or benign epithelioid cell patterns, the tumor was classified as not
benign. Clinical outcome was then correlated with the histologic designation
to determine if these preset criteria were valid. The authors were able to
classify the tumors as benign or not benign with a sensitivity of 100 percent
and specificity of 92 percent. For all cases, individual morphologic and clinical
features were examined. Features associated with an AO included tumor size
of 7 cm or greater, high cellularity, mucosal invasion, high nuclear grade,
mitotic counts of at least 5/50 high power fields, mixed cell type, and the
presence of a myxoid background or absence of stromal hyalinization. By recognizing
several well-defined patterns of benign gastric stromal tumors and the myriad
of individual features shown to correlate with an AO, one can better predict
the clinical behavior of gastric stromal tumors.
Trupiano JK, Stewart RE, Misick C, et al. Gastric stromal tumors. A clinicopathologic
study of 77 cases with correlation of features with nonaggressive and aggressive
clinical behaviors. Am J Surg Pathol. 2002;26:705-714.
Reprints: Dr. John R. Goldblum, Cleveland Clinic Foundation, 9500 Euclid
Ave., L25, Cleveland, OH 44195; goldblj@ccf.org
Endometrial stromal nodules and endometrial stromal tumors with limited infiltration
It is important to recognize the pathologic features of endometrial stromal
nodules to avoid confusing them with endometrial stromal sarcoma and other
tumors, such as uterine tumor resembling ovarian sex cord tumor. Features
that may be seen in endometrial stromal nodules, such as smooth muscle metaplasia,
irregular interdigitation of stromal neoplasia with metaplastic smooth muscle,
and broad zones of necrosis, may be confused with endometrial stromal sarcoma.
The authors emphasize the need for careful gross evaluation and thorough sampling
of the margin to avoid this confusion. In three of 50 cases, there were four
to six margin irregularities, with some extending from 3 mm to 9 mm beyond
the main border of the tumor (endometrial stromal tumor with limited infiltration).
These differed from endometrial stromal sarcoma based on the number and pattern
of the irregularities noted. Most tumors with margin irregularities had limited
followup precluding assessment of prognosis, however, the authors suspect
that most such tumors will behave in a benign fashion.
Dionigi A, Oliva E, Clement P, et al. Endometrial stromal nodules and endometrial
tumors with limited infiltration: a clinicopathologic study of 50 cases. Am
J Surg Pathol. 2002;26:567-581
Reprints: Dr. Esther Oliva, Dept. of Pathology, Massachusetts General Hospital,
55 Fruit St., Boston, MA 02114 |
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