The Frequency of Uterine Leiomyomas STEWART F. CRAMER, M.D. AND ARTI PATEL, B.A.
As a leading cause of hysterectomy in premenopausal women, uterine leiomyomas are a major public health problem. However, very little work has been done on their epidemiology. Indeed, their true frequency has never been established using systematic and meticulous methods. In this study, gross serial sectioning at 2-mm intervals was applied as an adjunct to routine pathology processing in 100 consecutive total hysterectomy specimens. This tripled the number of leiomyomas noted in routine pathology reports. There were 649 leiomyomas in 77 of 100 uteri, with multiplicity of leiomyomas in 84%. Although leiomyomas were more numerous and larger in women with a clinical diagnosis of myomatous uterus, the incidence was no higher than in uteri removed for other reasons. The postmenopausal incidence of leiomyomas was no lower than the premenopausal incidence, although postmenopausal leiomyomas were smaller and fewer. These findings suggest that epidemiologic studies of leiomyomas may not be valid if they are based only on clinical diagnoses or routine pathology reports. (Key words: Uterus; Leiomyoma; Hysterectomy; Pathology; Epidemiology) Am J Clin Pathol 1990;94:435-438
Department of Pathology, Rochester General Hospital, University of Rochester School of Medicine, Rochester, New York
AS A MAJOR cause of morbidity and a leading indication for hysterectomy in premenopausal women, uterine leiomyomas must be considered a major public health problem.1,9 Nonetheless, little is known about their epidemiology, etiology, or pathogenesis. 2 " 6 ' 9 " Indeed, even their frequency has not been the subject of systematic and meticulous study. Materials and Methods
Results
One hundred consecutive total hysterectomy specimens were grossly re-examined after their routine pathology examinations had been completed and reports issued. Thirty-three of the hysterectomies had a preoperative diagnosis of "myomatous uterus." Note was made of the clinical history, and of the routine pathology findings, and the routine microscopic sections were reviewed with particular attention to small, incidental, and clinically insignificant leiomyomas that might not have been mentioned in routine diagnostic reports. The gross specimens were
Received November 10, 1989; received revised manuscript and accepted for publication March 16, 1990. Miss Patel's current address is Northwestern University School of Medicine, Chicago, Illinois. Supported by a grant from the Rochester General Hospital Medical Research Fund. Presented at the Fall Meeting of the American Society of Clinical Pathologists, Las Vegas, October 1988. Address reprint requests to Dr. Cramer: Rochester General Hospital, 1425 Portland Avenue, Rochester, New York 14621.
The total number of leiomyomas identified by supplementing routine examination with serial gross sectioning at 2-mm intervals in these 100 uteri was 649, roughly threefold the number identified by routine examination. Of these, 178 were at least 1 cm in diameter; 202 were 5 9 mm in diameter; and 252 were 2-4 mm in diameter. All of these were grossly visible. Also included in the count were 17 nodules that were less than 2 mm in diameter, discovered incidentally in routine sections, and fulfilling the described microscopic criteria (Fig. 1). Although such nodules have long been referred to in the literature as seedling leiomyomas, some pathologists did not routinely record these or other clinically insignificant nodules that were less than 1 cm in diameter. Scrutiny of the 48 uteri without leiomyomas in the original reports revealed 67 small leiomyomas, occurring in 25 cases. Scrutiny of the other 52 uteri increased the number of leiomyomas to 582. Thus, scrutiny increased the incidence of leiomyomas by 48% (Table 1). It also
435
Downloaded from http://ajcp.oxfordjournals.org/ by guest on April 24, 2016
serially sectioned at 2-mm intervals to detect additional small leiomyomas that may have been missed on routine examination. Menopausal status was based on clinical data combined with endometrial histology. Leiomyomas were identified on gross examination as well-defined intramural, submucosal, or subserosal nodules, generally spherical and firm. They bulged from the cut surface, were white to tan, and usually had a whorled, trabecular pattern on the cut surface. Microscopic examination was not considered necessary for confirmation of diagnosis of mural nodules that had the usual appearance. This is the customary practice in virtually all pathology laboratories. When studied microscopically, leiomyomas generally were identified as well-circumscribed nodules composed of interlacing bundles of spindle shaped cells, with no mitotic activity and no significant nuclear atypia, in a stroma with varying degrees of fibrosis. We did not call hypercellular-appearing myometrium a leiomyoma unless it was nodular (Fig. 1).
436
A.J.C.P. • October 1990
CRAMER AND PATEL
-. J
***HB,J
, /
'•
•
.
/
_
As a leading cause of hysterectomy in premenopausal women, uterine leiomyomas are a major public health problem. However, very little work has been done on their epidemiology. Indeed, their true frequency has never been established using systematic and meticulous methods. In this study, gross serial sectioning at 2-mm intervals was applied as an adjunct to routine pathology processing in 100 consecutive total hysterectomy specimens. This tripled the number of leiomyomas noted in routine pathology reports. There were 649 leiomyomas in 77 of 100 uteri, with multiplicity of leiomyomas in 84%. Although leiomyomas were more numerous and larger in women with a clinical diagnosis of myomatous uterus, the incidence was no higher than in uteri removed for other reasons. The postmenopausal incidence of leiomyomas was no lower than the premenopausal incidence, although postmenopausal leiomyomas were smaller and fewer. These findings suggest that epidemiologic studies of leiomyomas may not be valid if they are based only on clinical diagnoses or routine pathology reports. (Key words: Uterus; Leiomyoma; Hysterectomy; Pathology; Epidemiology) Am J Clin Pathol 1990;94:435-438
Department of Pathology, Rochester General Hospital, University of Rochester School of Medicine, Rochester, New York
AS A MAJOR cause of morbidity and a leading indication for hysterectomy in premenopausal women, uterine leiomyomas must be considered a major public health problem.1,9 Nonetheless, little is known about their epidemiology, etiology, or pathogenesis. 2 " 6 ' 9 " Indeed, even their frequency has not been the subject of systematic and meticulous study. Materials and Methods
Results
One hundred consecutive total hysterectomy specimens were grossly re-examined after their routine pathology examinations had been completed and reports issued. Thirty-three of the hysterectomies had a preoperative diagnosis of "myomatous uterus." Note was made of the clinical history, and of the routine pathology findings, and the routine microscopic sections were reviewed with particular attention to small, incidental, and clinically insignificant leiomyomas that might not have been mentioned in routine diagnostic reports. The gross specimens were
Received November 10, 1989; received revised manuscript and accepted for publication March 16, 1990. Miss Patel's current address is Northwestern University School of Medicine, Chicago, Illinois. Supported by a grant from the Rochester General Hospital Medical Research Fund. Presented at the Fall Meeting of the American Society of Clinical Pathologists, Las Vegas, October 1988. Address reprint requests to Dr. Cramer: Rochester General Hospital, 1425 Portland Avenue, Rochester, New York 14621.
The total number of leiomyomas identified by supplementing routine examination with serial gross sectioning at 2-mm intervals in these 100 uteri was 649, roughly threefold the number identified by routine examination. Of these, 178 were at least 1 cm in diameter; 202 were 5 9 mm in diameter; and 252 were 2-4 mm in diameter. All of these were grossly visible. Also included in the count were 17 nodules that were less than 2 mm in diameter, discovered incidentally in routine sections, and fulfilling the described microscopic criteria (Fig. 1). Although such nodules have long been referred to in the literature as seedling leiomyomas, some pathologists did not routinely record these or other clinically insignificant nodules that were less than 1 cm in diameter. Scrutiny of the 48 uteri without leiomyomas in the original reports revealed 67 small leiomyomas, occurring in 25 cases. Scrutiny of the other 52 uteri increased the number of leiomyomas to 582. Thus, scrutiny increased the incidence of leiomyomas by 48% (Table 1). It also
435
Downloaded from http://ajcp.oxfordjournals.org/ by guest on April 24, 2016
serially sectioned at 2-mm intervals to detect additional small leiomyomas that may have been missed on routine examination. Menopausal status was based on clinical data combined with endometrial histology. Leiomyomas were identified on gross examination as well-defined intramural, submucosal, or subserosal nodules, generally spherical and firm. They bulged from the cut surface, were white to tan, and usually had a whorled, trabecular pattern on the cut surface. Microscopic examination was not considered necessary for confirmation of diagnosis of mural nodules that had the usual appearance. This is the customary practice in virtually all pathology laboratories. When studied microscopically, leiomyomas generally were identified as well-circumscribed nodules composed of interlacing bundles of spindle shaped cells, with no mitotic activity and no significant nuclear atypia, in a stroma with varying degrees of fibrosis. We did not call hypercellular-appearing myometrium a leiomyoma unless it was nodular (Fig. 1).
436
A.J.C.P. • October 1990
CRAMER AND PATEL
-. J
***HB,J
, /
'•
•
.
/
_
