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Mucous cysts of the vulvar vestibule
HUMAN PATHOLOGY-VOLUME 13, NUMBER 6 June 1982
MUCOUS CYSTS OF THE VULVAR VESTIBULE RICHARD
H.
01,
MD.,
AND ROBERT !vIUNN,
MS
iVIultiple mucous cysts ofthe vulvar vestibule are described, and the morphology, by both light and fine structure, is presented. The histogenesis of the lesion is also discussed. HUrl! Pothol 13:584586,1982. The presence of mucous cysts of the vulva has been well described and documented.v" They occur in women of all ages, more often as single rather than multiple lesions, and, frequently, are considered to be "inclusion 01' sebaceous cysts." They are confined to the vestibule and may occur in association with the subclitoral, paraurethral, or Bartholin duct ostia areas. They are submucosal in location, contain mucoid material, and are lined by a single layer of a tall columnar mucinous epithelium. They are benign lesions and are easily excised when they become symptomatic. These cysts have been thought to arise from either mesonephric," mullerian (paramesonephric)," or urogenital sinus endoderm.' A case of multiple mucous cysts of the vulvar vestibule is reported, and the light microscopic and fine structure of the cyst lining, as well as considerations of the histogenesis of the lesion, are described. REPORT OF A CASE The patient was a 27 -year-old woman, who had been experiencing increasingly painful swelling in the vulvar area, which became a source of dyspareuria and discomfort. She stated that the masses had been present for the last four to five years but only recently had become symptomatic. Physical examination revealed two submucosal, tensely cystic but freely movable masses on the vestibular portion of the right labium minus near the clitoral tissues. Excision was easily accomplished, and the cysts were fixed in Zenker solution with a portion in aldehyde solution for electron microscopy. The aldehyde solution consisted of 2 per cent para formaldehyde and 2.5 per cent glutaraldehyde in 0.06 moles of phosphate buffer. After fixation the specimen was dehydrated in acetone and embedded in Spurr epoxy resin" Thin sections were cut with diamond knives, mounted on grids, stained with uranyl acetate and lead citrate" and viewed in an AEI EM-801 electron microscope. RESULTS
Pathology The specimen consisted of two 1 X 2 X O.5-cm and 1 0.7 x 0.5-cm cystic masses containing a small amount of thick tenacious clear-white mucoid material. The cyst linings were smooth without any areas of thickening or any papillary excrescences. Histologically, the lining epithelium was a single layer of tall columnar cells with basally placed nuclei and finely granular amphophilic cytoplasm resembling normal endocervical-type epithelium (figure 1, inset). X
Received from the Department of Obstetrics and Gynecology and the Department of Pathology, University of California at Davis, Medical Center at Sacramento, Sacramento, Cal. Accepted for publication July 27, 1981. Address correspondence and reprint. request.s to Dr. Oi, Department of Obstetrics and Gynecology, University of California at Davis, Medical Center at Sacramento, 4301 X SI, Sacramento, CA 95817.
584
Special stains showed an intense PAS-positive reaction of the cytoplasm, which was unaffected by diastase. Mucicarmine stains were also very strongly positive. The immediately adjacent fibrous connective tissue showed a few inflammatory cells but no evidence of endometrial stromal cells and no smooth muscle or myoepithelial cells.
Ultrastructure The fine structure of the cyst lining showed tall columnar cells that rested on a prominent basal lamina. The lateral plasma membranes showed well-developed junctional ~0rr:tplexes at the apical surface, with prominent interdigitanons near the basal lamina. The nuclei were basally located and are very irregular in shape, with coarse, irregularly distributed chromatin and prominent nuclei. The abundant cytoplasm contained large numbers of apical secretory droplets, which showed coalescence, and droplets with a fibrillogranular texture (fig. 1). Several profiles of elongated fibrillar bodies were seen in each cell. The fibrillar contents of these bodies were observed in parallel arrays, tending to be arranged along the long axis (fig. 2). A few of these fibrillar bodies were seen to coalesce with more empty-appearing secretory droplets. Merocrine secretory activity was present near the luminal surface, which had prominent microvilli. The apical cytoplasm was virtually all secretory droplets and vesicles, with a few scattered mitochondria and lysosomes. The basal cytoplasm contained more mitochondria and profiles of rough-surfaced endoplasmic reticulum. No ciliated cells, goblet cells, or other intestinal type cells were identified. DISCUSSION Freidrich and Wilkinson' reported 20 cases of mucinous cysts of the vulva, reviewed the limited literature, identified the clinical and pathologic features of these lesions, and emphasized the recognition and excision of the cysts. They further suggested that the lesions are derived from cells of the urogenital sinus endoderm and that with sexual maturity and, possibly, hormonal stimulation, the lesions develop into cystic lesions. Novak and Woodruff'! suggested that the cysts arise from vestiges of the terminal portion of the wolffian (mesonephric) duct, but in a later edition of their work," they ascribe the origin of these cysts to mucinous epithelium displaced at the time of the division of the cloaca by the urorectal fold. Hart" suggested that these cysts are of rnullerian and, therefore, paramesonephric origin, because of their resemblance to the tall columnar mucinous epithelium of the endocervix. Freidrich and Wilkinson 1 concurred that histochemical and light morphologic findings indicate that the cyst lining is similar to endocervical epithelium but that the lining cells also resemble those of the parurethral and Bartholin gland systems derived from endodermal epithelium. They further commented that miiIlerian tissue does not contribute to the development of the lower genital tract, being limited in its caudad migration to the upper portion of the urogenital sinus and, therefore, the upper genital tract structures only. The fine structure of the cyst lining epithelium is also very similar to that of the endocervical epithelium," in which the cytoplasm contains numerous secretory granules that are closely associated with fibrillar bodies. These granular filamentous bodies are considered a form of gly-
0046-8177/8210600/0584 $00.60 © W. B. Saunders Co.
CAS E STUDIES
Figure 1 (toP). Columnar cells with prominent apical secretor y droplets, surface microvilli, an d promine nt basal lamina. Inset, cyst lining epitheliu m showin g single layer of tall columnar cells with basally plac ed nuclei. Figure 2 (bottom). Apical portion of th e cell with pr ominen t microvilli, sec retory drople ts tha t coalesce with fibrillar y bod ies, scattered mitoch ond ria, lysosomes, an d rou gh-su rfaced en dopl asmic retic ulu m.
585
HUMAN PATHOLOGY-VOLUME 13, NUMBER 6 June 1982 coprotein storage. Similar secretory granules and fibrillar structures are also seen in the mucus-secreting cells of Bartholin glands." The vulvar cyst lining epithelium in our case, unlike the normal endocervical epithelium. does not demonstrate any of the ciliated, nonsecretory cells that are very common in the endocervix. Nilsson" cites Guillon, who suggests that endocervical mucinous cells are transformed into ciliated cells toward the end of the menstrual cycle and that mucous cells, ciliated cells, and endometrial-type cells are characteristic of the endocervical epithelium. This was not seen in our fine-structure examination. It may be that vestibular mucous epithelium may not be responsive to progesterone or to other hormones, or that because of its derivation from endodermal tissues it does not possess the metaplastic potential to form ciliated cells and endometrial type cells that endocervical mullerian duct epithelium possesses. Freidrich and Wilkinson 1 also state that on ultrastructural examination, the lining cells in their cases were indistinguishable from mucus-producing cells located in the gastrointestinal tract, but we did not identify any intestinal-type epithelium in our case. The similarity, both by light and electron microscopy. of the vulvar vestibular mucus cyst lining epithelium to the mucus-secreting cells of the Bartholin and paraurethral gland systems suggests that they have a common origin in urogenital epithelium. The location of these cysts within the
vulvar vestibule, which develops as the pelvic and phallic portion of the urogenital sinus" also suggests that these cysts are most likely not derived from the miillerian or mesonephric duct system. We concur with Freidrich and Wilkinson t that vestibular mucous cysts are probably derived from urogenital sinus endoderm and are related to the development of the paraurethral, vestibular Bartholin gland system.'
References 1. Freidrich EG. Wilkinson EJ: Mucous cysts of the vulvar vestibule.
Obstet GynecoI42:407. 1973 2. Hart WR: Paramesonephric mucinous cysts of the vulva. Am J Obstet Gynecol 107: 1079. 1970 3. Novak ER. Woodruff JD: Gynecologic and Obstetric Pathology, 5th Ed. Philadelphia, WB Saunders Co, 1962. P 30 4. Spurr A:E: A low-viscosity epoxy resin embedding medium for electron microscopy. J Ultra Res 26:31. 1969 5. Reynolds ES: Abstract. J Cell Bioi 17:208, 1963 6. Novak ER, Woodruff JD: Gynecologic and Obstetric Pathology, 6th Ed. Philadelphia, WB Saunders Co. 1967, p 21 7. Ferenczy A, Richart RM: Female Reproductive System: Dynamics of Scan and Transmission Electron Microscopy. New York. john Wiley & Sons, 1974, p 71 8. Nilsson O. Westman A: The ultrastructure of the epithelial cells of the endocervix during the menstrual cycle. Acta Obsret Gynecol Scand 40:223,1961 9. Hamilton Wj, Boyd jD, Mossman HW: Human Embryology. Baltimore, Williams & Wilkins, 1962, p 298
FIBROUS HAMARTOMA OF INFANCY MARK
L.
MITCHELL,
MD, P.
A. DI SANT'AGNESE,
MD,
AND JOHN
A case offibrous hamartoma of infancy occurring in the scalp of a I-t-month-old is described. Light microscopy revealed features similar to those described preuiously. E lectron microscopic studies revealed cells with ulirastructurai characteristics of both fibroblasts and possibly myofibroblasts. In addition, occasional fusiform banded fibers (Luse bodies) were identified. This is thefirst reported case of a fibrous hamartoma of infancy in the scalp and the first description of its ultrastructural features. Hum Pathol13:586588,1982.
Fibrous hamartoma of infancy is a benign subcutaneous soft tissue tumor. It is relatively rare, occurring principally in white male infants less than 2 years old. The lesion, as described by Enzinger,' consists of mature adipose tissue interspersed with bundles of fibrous tissue and well-defined areas of more immature oval and stellate cells. Because of its high degree of cellularity and the presence of immature mesenchyme-like cells, erroneous diagnoses of malignancy have been made in some cases of this tumor. However, its biologic behavior is benign. Fibrous hamartoma of infancy has been described usually as a single tumor, most commonly in the subcutaneous tissue of the axilla, upper arm, neck, or t ru nk.J-" .• Single cases involving the foot," oropharynx," and perianal" and su praclavicular" areas have also been reported. The case presented here is unusual in that it is a fibrous hamartoma of infancy occurring in the scalp; this is the first report of such a lesion that includes ultrastructural studies.
Received from the University of Rochester Medical Center, Department of Pathology, Rochester, NY 14642. Accepted for publication August 4, 1982. Address correspondence and reprint requests to 01". Mitchell.
586
E. GERBER, MD
REPORT OF A CASE A 14-month-old white male infant was admitted to Strong Memorial Hospital for excision of a right parietooccipital scalp mass that had been found incidentally by his mother. Physical examination revealed that the lesion was 2 x 3 em; it was thought to be attached to the subcutaneous tissue of the skin. There was no evidence of inflammation. The other results of the child's physical examination and routine admission laboratory tests were normal. The patient recovered from the procedure uneventfully and was discharged three days later. MATERIALS AND METHODS The biopsy specimen was fixed in 10 per cent buffered formalin for routine light microscopy and histochemical examination. A section was obtained from the paraffin block for electron microscopy. It was postfixed in I per cent osmium tetroxide, dehydrated in alcohol, and embedded in Spurr epoxy resin. Thin sections were stained with uranyl acetate and lead citrate and examined in a Hitachi HS-8 electron microscope. RESULTS
Light Microscopy The specimen consisted of a 1.5 x 3-cm ellipse of skin with a poorly circumscribed, firm, glistening gray-white mass in the subcutaneous tissue. Light microscopic examination of the hematoxylin and eosin-stained sections revealed normal epidermis and dermis with underlying mature adipose tissue (fig. I). Intermixed with the adipose tissue were numerous well-formed trabeculae of dense fi-
0046-8177/8210600/0586 $00.60
© W. B. Saunders Co.
MUCOUS CYSTS OF THE VULVAR VESTIBULE RICHARD
H.
01,
MD.,
AND ROBERT !vIUNN,
MS
iVIultiple mucous cysts ofthe vulvar vestibule are described, and the morphology, by both light and fine structure, is presented. The histogenesis of the lesion is also discussed. HUrl! Pothol 13:584586,1982. The presence of mucous cysts of the vulva has been well described and documented.v" They occur in women of all ages, more often as single rather than multiple lesions, and, frequently, are considered to be "inclusion 01' sebaceous cysts." They are confined to the vestibule and may occur in association with the subclitoral, paraurethral, or Bartholin duct ostia areas. They are submucosal in location, contain mucoid material, and are lined by a single layer of a tall columnar mucinous epithelium. They are benign lesions and are easily excised when they become symptomatic. These cysts have been thought to arise from either mesonephric," mullerian (paramesonephric)," or urogenital sinus endoderm.' A case of multiple mucous cysts of the vulvar vestibule is reported, and the light microscopic and fine structure of the cyst lining, as well as considerations of the histogenesis of the lesion, are described. REPORT OF A CASE The patient was a 27 -year-old woman, who had been experiencing increasingly painful swelling in the vulvar area, which became a source of dyspareuria and discomfort. She stated that the masses had been present for the last four to five years but only recently had become symptomatic. Physical examination revealed two submucosal, tensely cystic but freely movable masses on the vestibular portion of the right labium minus near the clitoral tissues. Excision was easily accomplished, and the cysts were fixed in Zenker solution with a portion in aldehyde solution for electron microscopy. The aldehyde solution consisted of 2 per cent para formaldehyde and 2.5 per cent glutaraldehyde in 0.06 moles of phosphate buffer. After fixation the specimen was dehydrated in acetone and embedded in Spurr epoxy resin" Thin sections were cut with diamond knives, mounted on grids, stained with uranyl acetate and lead citrate" and viewed in an AEI EM-801 electron microscope. RESULTS
Pathology The specimen consisted of two 1 X 2 X O.5-cm and 1 0.7 x 0.5-cm cystic masses containing a small amount of thick tenacious clear-white mucoid material. The cyst linings were smooth without any areas of thickening or any papillary excrescences. Histologically, the lining epithelium was a single layer of tall columnar cells with basally placed nuclei and finely granular amphophilic cytoplasm resembling normal endocervical-type epithelium (figure 1, inset). X
Received from the Department of Obstetrics and Gynecology and the Department of Pathology, University of California at Davis, Medical Center at Sacramento, Sacramento, Cal. Accepted for publication July 27, 1981. Address correspondence and reprint. request.s to Dr. Oi, Department of Obstetrics and Gynecology, University of California at Davis, Medical Center at Sacramento, 4301 X SI, Sacramento, CA 95817.
584
Special stains showed an intense PAS-positive reaction of the cytoplasm, which was unaffected by diastase. Mucicarmine stains were also very strongly positive. The immediately adjacent fibrous connective tissue showed a few inflammatory cells but no evidence of endometrial stromal cells and no smooth muscle or myoepithelial cells.
Ultrastructure The fine structure of the cyst lining showed tall columnar cells that rested on a prominent basal lamina. The lateral plasma membranes showed well-developed junctional ~0rr:tplexes at the apical surface, with prominent interdigitanons near the basal lamina. The nuclei were basally located and are very irregular in shape, with coarse, irregularly distributed chromatin and prominent nuclei. The abundant cytoplasm contained large numbers of apical secretory droplets, which showed coalescence, and droplets with a fibrillogranular texture (fig. 1). Several profiles of elongated fibrillar bodies were seen in each cell. The fibrillar contents of these bodies were observed in parallel arrays, tending to be arranged along the long axis (fig. 2). A few of these fibrillar bodies were seen to coalesce with more empty-appearing secretory droplets. Merocrine secretory activity was present near the luminal surface, which had prominent microvilli. The apical cytoplasm was virtually all secretory droplets and vesicles, with a few scattered mitochondria and lysosomes. The basal cytoplasm contained more mitochondria and profiles of rough-surfaced endoplasmic reticulum. No ciliated cells, goblet cells, or other intestinal type cells were identified. DISCUSSION Freidrich and Wilkinson' reported 20 cases of mucinous cysts of the vulva, reviewed the limited literature, identified the clinical and pathologic features of these lesions, and emphasized the recognition and excision of the cysts. They further suggested that the lesions are derived from cells of the urogenital sinus endoderm and that with sexual maturity and, possibly, hormonal stimulation, the lesions develop into cystic lesions. Novak and Woodruff'! suggested that the cysts arise from vestiges of the terminal portion of the wolffian (mesonephric) duct, but in a later edition of their work," they ascribe the origin of these cysts to mucinous epithelium displaced at the time of the division of the cloaca by the urorectal fold. Hart" suggested that these cysts are of rnullerian and, therefore, paramesonephric origin, because of their resemblance to the tall columnar mucinous epithelium of the endocervix. Freidrich and Wilkinson 1 concurred that histochemical and light morphologic findings indicate that the cyst lining is similar to endocervical epithelium but that the lining cells also resemble those of the parurethral and Bartholin gland systems derived from endodermal epithelium. They further commented that miiIlerian tissue does not contribute to the development of the lower genital tract, being limited in its caudad migration to the upper portion of the urogenital sinus and, therefore, the upper genital tract structures only. The fine structure of the cyst lining epithelium is also very similar to that of the endocervical epithelium," in which the cytoplasm contains numerous secretory granules that are closely associated with fibrillar bodies. These granular filamentous bodies are considered a form of gly-
0046-8177/8210600/0584 $00.60 © W. B. Saunders Co.
CAS E STUDIES
Figure 1 (toP). Columnar cells with prominent apical secretor y droplets, surface microvilli, an d promine nt basal lamina. Inset, cyst lining epitheliu m showin g single layer of tall columnar cells with basally plac ed nuclei. Figure 2 (bottom). Apical portion of th e cell with pr ominen t microvilli, sec retory drople ts tha t coalesce with fibrillar y bod ies, scattered mitoch ond ria, lysosomes, an d rou gh-su rfaced en dopl asmic retic ulu m.
585
HUMAN PATHOLOGY-VOLUME 13, NUMBER 6 June 1982 coprotein storage. Similar secretory granules and fibrillar structures are also seen in the mucus-secreting cells of Bartholin glands." The vulvar cyst lining epithelium in our case, unlike the normal endocervical epithelium. does not demonstrate any of the ciliated, nonsecretory cells that are very common in the endocervix. Nilsson" cites Guillon, who suggests that endocervical mucinous cells are transformed into ciliated cells toward the end of the menstrual cycle and that mucous cells, ciliated cells, and endometrial-type cells are characteristic of the endocervical epithelium. This was not seen in our fine-structure examination. It may be that vestibular mucous epithelium may not be responsive to progesterone or to other hormones, or that because of its derivation from endodermal tissues it does not possess the metaplastic potential to form ciliated cells and endometrial type cells that endocervical mullerian duct epithelium possesses. Freidrich and Wilkinson 1 also state that on ultrastructural examination, the lining cells in their cases were indistinguishable from mucus-producing cells located in the gastrointestinal tract, but we did not identify any intestinal-type epithelium in our case. The similarity, both by light and electron microscopy. of the vulvar vestibular mucus cyst lining epithelium to the mucus-secreting cells of the Bartholin and paraurethral gland systems suggests that they have a common origin in urogenital epithelium. The location of these cysts within the
vulvar vestibule, which develops as the pelvic and phallic portion of the urogenital sinus" also suggests that these cysts are most likely not derived from the miillerian or mesonephric duct system. We concur with Freidrich and Wilkinson t that vestibular mucous cysts are probably derived from urogenital sinus endoderm and are related to the development of the paraurethral, vestibular Bartholin gland system.'
References 1. Freidrich EG. Wilkinson EJ: Mucous cysts of the vulvar vestibule.
Obstet GynecoI42:407. 1973 2. Hart WR: Paramesonephric mucinous cysts of the vulva. Am J Obstet Gynecol 107: 1079. 1970 3. Novak ER. Woodruff JD: Gynecologic and Obstetric Pathology, 5th Ed. Philadelphia, WB Saunders Co, 1962. P 30 4. Spurr A:E: A low-viscosity epoxy resin embedding medium for electron microscopy. J Ultra Res 26:31. 1969 5. Reynolds ES: Abstract. J Cell Bioi 17:208, 1963 6. Novak ER, Woodruff JD: Gynecologic and Obstetric Pathology, 6th Ed. Philadelphia, WB Saunders Co. 1967, p 21 7. Ferenczy A, Richart RM: Female Reproductive System: Dynamics of Scan and Transmission Electron Microscopy. New York. john Wiley & Sons, 1974, p 71 8. Nilsson O. Westman A: The ultrastructure of the epithelial cells of the endocervix during the menstrual cycle. Acta Obsret Gynecol Scand 40:223,1961 9. Hamilton Wj, Boyd jD, Mossman HW: Human Embryology. Baltimore, Williams & Wilkins, 1962, p 298
FIBROUS HAMARTOMA OF INFANCY MARK
L.
MITCHELL,
MD, P.
A. DI SANT'AGNESE,
MD,
AND JOHN
A case offibrous hamartoma of infancy occurring in the scalp of a I-t-month-old is described. Light microscopy revealed features similar to those described preuiously. E lectron microscopic studies revealed cells with ulirastructurai characteristics of both fibroblasts and possibly myofibroblasts. In addition, occasional fusiform banded fibers (Luse bodies) were identified. This is thefirst reported case of a fibrous hamartoma of infancy in the scalp and the first description of its ultrastructural features. Hum Pathol13:586588,1982.
Fibrous hamartoma of infancy is a benign subcutaneous soft tissue tumor. It is relatively rare, occurring principally in white male infants less than 2 years old. The lesion, as described by Enzinger,' consists of mature adipose tissue interspersed with bundles of fibrous tissue and well-defined areas of more immature oval and stellate cells. Because of its high degree of cellularity and the presence of immature mesenchyme-like cells, erroneous diagnoses of malignancy have been made in some cases of this tumor. However, its biologic behavior is benign. Fibrous hamartoma of infancy has been described usually as a single tumor, most commonly in the subcutaneous tissue of the axilla, upper arm, neck, or t ru nk.J-" .• Single cases involving the foot," oropharynx," and perianal" and su praclavicular" areas have also been reported. The case presented here is unusual in that it is a fibrous hamartoma of infancy occurring in the scalp; this is the first report of such a lesion that includes ultrastructural studies.
Received from the University of Rochester Medical Center, Department of Pathology, Rochester, NY 14642. Accepted for publication August 4, 1982. Address correspondence and reprint requests to 01". Mitchell.
586
E. GERBER, MD
REPORT OF A CASE A 14-month-old white male infant was admitted to Strong Memorial Hospital for excision of a right parietooccipital scalp mass that had been found incidentally by his mother. Physical examination revealed that the lesion was 2 x 3 em; it was thought to be attached to the subcutaneous tissue of the skin. There was no evidence of inflammation. The other results of the child's physical examination and routine admission laboratory tests were normal. The patient recovered from the procedure uneventfully and was discharged three days later. MATERIALS AND METHODS The biopsy specimen was fixed in 10 per cent buffered formalin for routine light microscopy and histochemical examination. A section was obtained from the paraffin block for electron microscopy. It was postfixed in I per cent osmium tetroxide, dehydrated in alcohol, and embedded in Spurr epoxy resin. Thin sections were stained with uranyl acetate and lead citrate and examined in a Hitachi HS-8 electron microscope. RESULTS
Light Microscopy The specimen consisted of a 1.5 x 3-cm ellipse of skin with a poorly circumscribed, firm, glistening gray-white mass in the subcutaneous tissue. Light microscopic examination of the hematoxylin and eosin-stained sections revealed normal epidermis and dermis with underlying mature adipose tissue (fig. I). Intermixed with the adipose tissue were numerous well-formed trabeculae of dense fi-
0046-8177/8210600/0586 $00.60
© W. B. Saunders Co.