Collagen balls in a cervical‐vaginal smear: A case report

Collagen balls are balls of collagen (spheroid, ellipsoid or papillary) occasionally covered with mesothelial cells and found sporadically in peritoneal effusions or washings. However, Collagen balls in cervical-vaginal smears are a relatively rare finding. We report a case of collagen balls in the cervical smear of a 64-year-old Caucasian woman. She was a postmenopausal, sexually inactive woman, who presented for her routine annual screening for cervical dysplasia or carcinoma. The patient did not complain of vaginal bleeding or other symptoms. Her physical examination was unremarkable except for atrophic vaginitis. Her past medical history was significant for cancer of the left breast treated with mastectomy and tamoxifen 13 years ago. She never received any hormone replacement therapy. She has had no intraabdominal or pelvic surgery. Two prior cervical smears on record revealed parabasal atrophy and inflammation with no other pathologic findings. In our case, a BD SurePath specimen was routinely stained with Papanicolaou stain. Microscopic examination revealed numerous three-dimensional, semitranslucent, individual structures with spheroid or elliptical shapes that are smoothly contoured. The structures displayed a lamellar pattern and appeared green-turquoise, green or dichromatic green, and orange cores (Fig. C-1). Their size ranged from 20 to 100 micrometers (average size 50 micrometers) in greatest dimension. Some of them were partially or completely covered by flattened epithelial cells (Fig. C-2). The cells maintain low nuclear/cytoplasmic ratios with smooth nuclear membrane and uniform chromatin. A few of these structures were cracked (Fig. C-3). The pap smear was otherwise negative for intraepithelial lesion or cancer and displayed estrogen effect with reactive inflammatory changes. Collagen balls were first described in peritoneal washings in 1992. These collagen balls appear to be fragments of collagenous tissue covered with mesothelial cells. These findings have been confirmed by cytokeratin and vimentin expression of the epithelial cells confirming their mesothelial origin and staining of collagen balls with collagen types I and III. Collagen balls are rarely seen in cervical-vaginal smears. To date, only two case series have been published describing collagen balls in cervical smears. Sahoo reported collagen balls in five conventional cervical smears for first time in 2004. Later, Szporn et al. reported collagen balls in three conventional cervical-vaginal smears and four ThinPrep specimens. Our case is the first reported case of collagen balls in a SurePath preparation cervical-vaginal smear. We also noted scattered collagen balls with cracks at the periphery which has not been reported. Reviewing our case and all previously reported cases fails to show any trends or correlation among patient age, phase in the menstrual cycle, cytologic findings in the pap smears, and history of any previous abdominal surgery or presence of apparent peritoneal or gynecologic lesions with the presence of collagen balls. The origin of these balls is controversial. It has been suggested that these collagen balls originate in mesothelium-covered organs and are subsequently transported via the fallopian tubes into the uterus. The etiology and significance of collagen balls in cervical-vaginal smears also remain undetermined. These structures can be mistaken for mucin-distended cells exfoliated from a neoplasm or from detached fragments of a papillary ovarian neoplasm. Corpora amylacea are another noncellular structures that can be occaMatthew Tilson is a pathology Resident at The Johns Hopkins University. Zahra Maleki is an Instructor in Pathology. Department of Pathology, Division of Cytopathology, The Johns Hopkins Medical Institutions, Baltimore, Maryland