Epidermoid Cyst of the Ovary

Transcription

1 Epidermoid Cyst of the Ovary A eport of Three Cases with Comments on Histogenesis OBET H. YOUNG, M.B., JAIME PAT, M.D., AND OBET E. SCUY, M.D. Young, obert H., Prat, Jaime, and Scully, obert E.: Epidermoid cyst of the ovary. A report of three cases with comments on histogenesis. Am J Clin Pathol 7: 7-7, Three cases of epidermoid cyst of the ovary are presented. In each case small epithelial nests were found in the wall of the cyst, which, on serial section, proved to be focally cystic with mucin and keratin debris in their lumens. A comparative study of these epithelial nests, Walthard nests, and the epithelial components of a Brenner tumor revealed striking morphologic similarities. The findings suggest that epidermoid cysts originate from epithelial cell nests of the type encountered in Brenner tumors. (Key words: Ovary; Epidermoid cyst; Epithelial nests.) THE HISTOGENESIS of gonadal epidermoid cysts, defined as cysts lined by epidermis unaccompanied by skin appendages or other teratomatous elements, is controversial. In a review of 9 cysts arising in the testis, Price" favored a teratomatous origin, although an alternative explanationcystic dilatation of the rete with squamous metaplasia of its epitheliumhad previously been suggested. 4 Epidermoid cysts are very rare in the ovary,' 1 in contrast to the dermoid cyst, which is one of the ovary's most common benign tumors. In a report of two cases of epidermoid cyst, More" proposed several possible origins, including cystic dilatation and squamous metaplasia of the rete ovarii, squamous metaplasia of a surface epithelial inclusion cyst, implantation of skin during a previous operation, and monophyletic development of a teratoma. Other explanations, such as cystic dilatation of a hilar mesonephric tubule with squamous metaplasia of its epithelium"' and metaplasia of the lining of an endometriotic cyst, have also been offered. 7 In the World Health Organization classification of ovarian tumors, epidermoid cysts are included under teratomas of monodermal and highly specialized type. 10 In a report of five cases, Nogales and Silverberg 8 have presented ultrastructural evidence that some of these cysts arise by metaplasia of the coelomic epithelium, but they concluded that others were of teratomatous eceived February ; accepted for publication March c Address reprints to Dr. Young: Department of Pathology, Massachusetts General Hospital. Boston. Massachusetts Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts origin. We have encountered three cases in which epithelial nests similar to Walthard nests and the epithelial aggregates found in Brenner tumors were present in the walls of epidermoid cysts. The nests were subjected to detailed morphologic investigation. We have found no previous description or illustration of these nests in relation to epidermoid cysts in the medical literature. Clinical and Pathologic Data The clinical and pathologic features of our three cases and the seven previously reported cases 08 are presented in Table 1. The cysts ranged from to 4 mm in diameter. When visible, they appeared as oval or round cysts containing yellow-white material of creamy consistency (Fig. 1). In all the cases, the lesion was an incidental finding. The patients ranged in age from 1 to 4 years. Five cysts were located in the left ovary and five in the right ovary. Of the previously reported cases, four were subcortical, two hilar and one medullary. Our three cysts were situated in the medulla. Direct continuity with the surface epithelium was not demonstrated in any of the cases. Histologic examination of the cysts in the present series showed a thin lining of mature keratinizing squamous epithelium surrounded by a fibrous capsule in which small nests of epithelial cells were found (Fig. ). These cells were oval or polygonal with clear cytoplasm and central nuclei in which grooves were visible (Fig. ). One or two small nucleoli were present in most of the nuclei. The cells closely resembled the transitional-type cells encountered in Walthard nests and the epithelial units of Brenner tumors. Serial sections in each of our cases revealed that the nests became cystic with a change in the epithelium to a squamous type (Fig. 4) and an appearance in the nest lumens of keratin and keratinized cells embedded in pink-staining material, which was mucicarmine-positive /80/000/07 $00.75 American Society of Clinical Pathologists 7

2 Vol. 7 No. CASE EPOTS 7 FIG. I. Case I. Epidermoid cyst of the ovary. and periodic acid-schiff (PAS)-positive, diastaseresistant (Fig. 5). No intracellular mucin could be demonstrated. As the nests became more cystic and their linings underwent squamous metaplasia, the amount of mucin in the lumens decreased. No mucin could be demonstrated in the major cysts. Mucicarmine, PAS, and PAS with diastase stains of histologically typical Walthard nests and the epithelial units of a Brenner tumor showed similar mucin positivities in the lumens. The mural nests became very closely apposed to the major cysts on serial sectioning, but communication of their lumens was not demonstrable. Adjacent to the cyst in Case was a nodule 1 mm in diameter consisting of glands lined by ciliated columnar cells with Table 1. Epidermoid Cyst of the Ovary Case No. Age of Patient (Years) Side ocation Size (mm) Other Findings More Nogales and Silverberg Case Case 4 Case Hilar Hilar Follicle cysts eiomyomas of uterus Adenomyosis of uterus eiomyomas of uterus Endometrial adenoacanthoma Young el ul. Case Dermoid cyst, right ovary Serous cystadenoma Adjacent adenomyoma; surface epithelial inclusion cysts: endometrioma, left ovary

3 74 YOUNG. PAT, AND SCUY A.J.C.I'. February 1980 FIG. {upper).. Keratinizing epidermoid cyst with fibrous capsule in which nests of epithelial cells can be seen. Hematoxylin and eosin. X5. FIG. {lower).. Nest of transitional-type epithelial cells in wall of cyst. Hematoxylin and eosin. X5. intervening smooth muscle (Fig. ). PAS, PAS with diastase, and mucicarmine stains showed staining of material in the lumens of the glands, as well as within their lining cells. The ovary in this case also contained several surface epithelial inclusion cysts. No such cyst was found in our other two cases. Discussion Epidermoid cysts of the ovary are of interest mainly because their histogenesis is uncertain. Along with other ovarian lesions characterized by cells that are not of obvious mesodermal origin, these cysts have

4 Vol. 7 No. CASE EPOTS 75 FIG. 4. Deeper section of nest in, showing cystic change with keratinization of lining epithelium. Hematoxylin and eosin. x70. Insert shows squamous epithelium of major cyst and mural cyst al level of closest apposition. Keratohyaline granules can be seen in the epithelium of both cysts. Hematoxylin and eosin. x40. * «* i "' - * -, ' ' :.*, fi. " - :.:;. ^ ^, - * : - \ * < - S ' * ISIA??^ I*^""4.<>AI^' & > '''-.">», :..-** \ < ^ < FIG. 5. Cystic nest in Case, showing darker-staining mucicar minophilic material and central lighter-staining keratin in lumen Mucicarmine stain. xloo. FIG.. Adenomyoma adjacent to epidermoid cyst in Case. Hematoxylin and eosin. x.

5 7 YOUNG, PAT, AND SCUY A.J.C.P. February 1980 been considered by some to be monophyletic teratomas. A similar nature has been suggested for pure epidermoid cysts of the testis, 9 but their invariably benign course, which differs from the sometimes malignant behavior of mature testicular teratomas of heterogeneous composition, is evidence against such an interpretation. More" has suggested that if epidermoid cysts of the ovary arise by squamous metaplasia, an origin from the surface epithelium should be considered in view of the occurrence of squamous differentiation in some ovarian surface epithelial tumors. NogdlSs and Silverberg, in a report of five cases of epidermoid cyst, described one in which ultrastructural examination of the lining cells revealed findings characteristic of the cells of Walthard nests and the epithelial islands of Brenner tumors. 8 Our demonstration of nests of Walthard or Brenner type in the walls of three epidermoid cysts provides the most direct evidence of a close relation of these cysts to the Brenner tumor and suggests similar origins. The histogenesis of the Brenner tumor is controversial, and the proposed cells of origin include rete epithelial cells, germ cells, and surface epithelial cells. 1 - The location of only two of the ten cases of epidermoid cyst in the hilus argues against the origin of the majority from the rete. The failure to demonstrate tissue of definite endodermal or mesodermal origin on serial sectioning of blocks in our cases and in cases reported elsewhere is evidence against a teratomatous nature unless the lesion reflects monophyletic development of a germ cell tumor. However, the presence of a dermoid cyst in the contralateral ovary in our supports the possibility of a germ cell origin. The proximity of an adenomyomatous nest with ciliated cells as well as the presence of several surface epithelial inclusion glands in our Case, on the other hand, favors an origin from surface epithelium. Although the ultimate derivation of epidermoid cysts of the ovary remains a mystery, the formation of epithelial nests similar to those of the Brenner tumor appears to be an early stage in their development. eferences 1. Bransilver B, Ferenczy A, ichart M: Brenner tumors and Walthard cell nests. Arch Pathol ab Med 98:7-8, Fox H, angley FA: Tumors of the Ovary. Chicago Yearbook Medical Publishers, 197, p 109. Fox H, angley FA: Tumors of the Ovary. Chicago Yearbook Medical Publishers, 197, p Halley JBW: Epidermoid cysts of the testicles. J Pathol 8:7-7, Jirasek JE: A contribution to the development of epidermoids in the hilar region of the ovary (in Czech). Csl Morfol 8:0-, 190. More JS: Epidermoid cyst of the ovary. Gynaecol Invest 14:40-48, Motlik K: Ovarian neoplasms, morphology and classification. Acta Univ Carol [Med Monogr] (Praha) 44:, Nogales FF, Silverberg SG: Epidermoid cysts of the ovary: a report of five cases with histogenic considerations and ultrastructural findings. Am J Obstet Gynecol 14:5-58, Price EB: Epidermoid cysts of the testis: a clinical and pathologic analysis of 9 cases from the testicular tumor registry. J Urol 10: Serov SF, Scully E. Sobin H: Histological Typing of Ovarian Tumors. World Health Organization, Geneva, 197, p49 Inflammatory Malignant Fibrous Histiocytoma MAIA J. MEINO, M.D., AND VIGINIA A. ivosi, M.D. Merino, Maria J., and ivoisi, Virginia A.: Inflammatory malignant fibrous histiocytoma. Am J Clin Pathol 7: 7-81, This report describes a 1-year-old girl with inflammatory malignant fibrous histiocytoma of the abdomen. Clinical, pathologic, and ultrastructural features of this subgroup of tumors are discussed. Differential diagnostic criteria are reviewed. (Key words: Inflammatory malignant fibrous histiocytoma; Xanthogranuloma; Pediatric tumors.) eceived December : received revised manuscript and accepted for publication March, Address reprint requests to Dr. ivoisi: Department of Pathology, Yale University School of Medicine, 10 Cedar Street, New Haven, Connecticut Department of Pathology, Yale University School of Medicine, New Haven, Connecticut INFAMMATOY FIBOUS histiocytoma describes a lesion that resembles a xanthogranuloma and has a prominent neutrophilic infiltrate, but which behaves as an aggressive neoplasm. 10 ' 4 We prefer the term inflammatory malignant fibrous histiocytoma, since this lesion, despite its appearance, fulfills the biologic criteria of a sarcoma /80/000/07 $00.80 American Society of Clinical Pathologists