Massive multilocular cystic leiomyoma of the uterus: an extreme example of hydropic degeneration.

Abstract: A 49-year-old woman underwent laparotomy for an undiagnosed, extremely large abdominal mass. At surgery, this was discovered to be a uterine tumor and she was subjected to a subtotal hysterectomy. Pathologic examination of the uterus revealed a multilocular cystic mass containing over 18 L of fluid that was established on histology to be a markedly hydropic leiomyoma. This case describes a very uncommon growth pattern of leiomyoma of the uterus that has only been occasionally described previously. We propose the name multilocular, cystic leiomyoma for this variant.

Key Words: uterus, leiomyoma, hydropic degeneration, multilocular cyst, smooth muscle uterine neoplasm 

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Leiomyomas of the uterus are common tumors and previous observations and reports have resulted in well-recognized diagnostic categories based on histologic or gross differences. This report describes a leiomyoma which was distinctive because of its massive size and its multicystic appearance, creating considerable clinical and gross pathologic diagnostic dilemmas, as well as a surgical challenge. The main aim of this paper is to review the characteristics of presently recognized leiomyomas of the uterus with unusual growth patterns and add another unusual variant of this otherwise common tumor to the literature.

Case Report

This patient first presented as a 43-year-old para 3 + 1 to the gynecology clinic at the University Hospital of the West Indies with a history of menorrhagia and lower abdominal pain. She had no other known medical problems. Examination revealed a 20-week sized pelvic mass. She was assessed as having symptomatic uterine fibroids and was scheduled for a hysterectomy. However, the patient defaulted from the clinic.

She presented 6 years later, now 3 years postmenopausal, with a history of a slow, progressive increase in abdominal girth since last seen medically. Besides moderate discomfort from the markedly increased abdominal girth, there were no other accompanying symptoms. Abdominal examination revealed a massively distended, pendulous abdomen associated with an intra-abdominal mass. There was marked edema of the infraumbilical abdominal skin with visible peau d'orange. A computed tomography scan revealed a heterogeneous mass arising from the pelvis. Although the mass was thought to be closely related to the uterus and the sigmoid colon, the exact origin was undetermined. In fact, following this investigation, a provisional diagnosis of intra-abdominal desmoid tumor was suggested. A core needle biopsy of the mass was performed which revealed only benign spindle cells, but the nature of the tumor remained indeterminate. The patient, therefore, was subjected to an exploratory laparotomy.

At surgery, the large mass was noted to be arising from the uterus. A subtotal abdominal hysterectomy with bilateral salpingectomy was performed concurrently with abdominoplasty to excise redundant abdominal wall skin. The patient's postoperative course was uneventful and she was discharged from the hospital 5 days after surgery. At her last follow-up visit, 24 months since the operation, she was in good health with no significant complaints.

[FIGURE 1 OMITTED]

The specimen consisted of a massive, lobulated, apparently cystic tumor, 60 X 42.5 X 22.7 cm, which was attached to the left side of a 12.8 X 10.2 X 7.5 cm corpus uterus (Fig. 1A). The total specimen weighed 33.8 kg. Further sectioning confirmed the multiloculated, cystic character of the tumor with cysts ranging from barely visible to 15 cm in diameter. All but one locule contained clear, serous fluid which cumulatively approximated 18 L in volume. One locule contained approximately 500 mL of congealed hemorrhagic material. The lining of the fluid-filled cavities was smooth throughout and the separating walls varied in thickness from a few millimeters to 7 cm. In these solid portions of the mass, the tissue was white and focally exhibited a whorled appearance. The large cystic lesion was continuous with an intrauterine solid mass, from which it could not be delineated, occupying most of the uterus (Fig. 1B). The endometrial cavity was reduced to a slit inferiorly by the large in-tramyometrial component of the mass.

Histologically, sections of the solid portions of the tumor revealed a proliferation of cytologically benign, mitotically inactive, smooth muscle cells that focally demonstrated a whorled pattern as is typical of a "garden variety" leiomyoma. The most noteworthy feature of the lesion, however, was the marked generalized hydropic degeneration (Fig. 2) that in places, was associated with splaying of individual muscle cells (Fig. 3A) and elsewhere culminated in widespread microcystic formation (Fig. 3B). Other noteworthy features included focal thick-walled blood vessels that were particularly prominent in the intramural portion of the tumor. A thin rim of normal myometrium was stretched over the tumor in the sections taken from the uterus and many of those taken from the periphery of the larger tumor mass. The overall histologic picture was interpreted as one of a markedly hydropic, grossly multilocular, cystic leiomyoma.

Histologic examination of the endometrium revealed atrophy, while that of the fallopian tubes was unremarkable.

Discussion

Leiomyomas of the uterus are common neoplasms and the vast majority are of the conventional type and are therefore easy to diagnose. Over the years, a number of histologic subtypes have been described, their importance largely due to their resemblance to leiomyosarcoma, in one or more aspects, with the obvious potential for misdiagnosis. In addition to these histologic subtypes, there has been the continuing recognition of an increasing number of leiomyomas with unusual growth patterns, generally recognized by their gross appearances. It is this latter group of tumors that we reviewed in our attempt to accurately categorize this specimen.

[FIGURE 2 OMITTED]

[FIGURE 3 OMITTED]

Diffuse leiomyomatosis is among the many variants of uterine leiomyoma with unusual growth patterns that have been described. (1) This tumor, however, is characterized by uterine enlargement that is symmetric, the result of innumerable leiomyomatous nodules throughout the myometrium. Not only was the present uterus with its contained tumor markedly distorted in shape, but there was no indication of multiple lesions. Another recognized morphologic variant of leiomyoma is intravenous (IV) leiomyomatosis (2); the presence of leiomyomas within vascular spaces outside of a leiomyoma, which are often grossly visible. This was not a credible differential diagnosis in our patient. One of the newer, relatively rare variants, the cotyledonoid leiomyoma, (3) has been the subject of a number of recent case reports, (4,5) a result, no doubt, of its dramatic placental-like gross appearance which belies its otherwise benign nature. While extending beyond the limits of the uterine corpus, the characteristic cotyledonoid component resembling placental tissue was not a feature of the present tumor, thus excluding this particular variant in our differential diagnosis.

The main abnormality in this case appeared to be that of severe and extensive hydropic degeneration in a leiomyoma which resulted in a prominent multilocular cystic structure that more closely resembled a serous cystic ovarian neoplasm on gross examination. Clement et al (6) reported on a series of leiomyomas that were accompanied by hydropic degeneration both within and adjacent to these tumors. In some cases, the hydropic change resulted in the now well-recognized peri-nodular hydropic pattern that may simulate IV leiomyomatosis. This pattern has since been reported by others. (7,8) The tumors in Clement et al's series reached a maximum size of 10 cm, and although noting "focal cystic change" in four cases, this characteristic was clearly not striking. This is in sharp contrast to the leiomyoma in this case wherein the cysts were prominent, grossly visible and large, resulting in a much larger tumor with a maximum dimension of 60 cm that contained up to 18 L of clear fluid. It is noteworthy that reference was made in that publication to two previously reported tumors during the early part of the last century, associated with massive fluid accumulation that might have been similar to ours. However, such extreme examples are obviously very uncommon. Our review of the more recent literature has unearthed only a few other similar, though perhaps less dramatic, cases in the English literature (9,10,11) and at least two others in the non-English literature. (12,13) Interestingly, two of these cases (9,10) reported presentation with pseudo-Meigs syndrome and elevated serum CA-125, no doubt adding to the clinical diagnostic dilemma.

Leiomyomas of the uterus are often accompanied by degenerative changes including hyalinization, myxoid change, and calcification. (14) The presence of edema within these tumors is also considered to be another type of degenerative process which, when less severe, is often referred to as hydropic change (15) or hydropic degeneration. (6) Cyst formation can be considered an exaggeration of this process, associated with increasing amounts of edematous fluid in some tumors. While cystic change, in itself, is also a recognized degenerative phenomenon, such extreme and extensive macrocystic transformation appears unusual and obviously contributed to the extremely large size of this lesion.

This patient's age was typical of that of most patients with unusual leiomyomas. Most variant leiomyomas have been reported in patients in the latter phase of reproductive life or in the perimenopausal period. As with other leiomyomas with unusual growth patterns, this one appears to have been entirely benign and the patient's prognosis is good.

Conclusion

In summary, we have described an example of extreme hydropic degeneration in a uterine leiomyoma, associated with a highly unusual gross appearance. Only a few similar cases have been previously reported. The histologic picture was, in contrast, rather mundane, at least in some parts of the tumor. Due to its massive size, this tumor presented not only a preoperative diagnostic dilemma, but a surgical challenge, as well. We think that the name multilocular, cystic leiomyoma is appropriate for this variant.

References

1. Clement PB, Young RH. Diffuse leiomyomatosis of the uterus: a report of four cases. Int J Gynecol Pathol 1987;6:322-330.

2. Norris HJ, Parmley T. Mesenchymal tumors of the uterus. V. Intravenous leiomyomatosis. A clinical and pathologic study of 14 cases. Cancer 1975;36:2164-2178.

3. Roth LM, Reed RJ, Sternberg WH. Cotyledonoid dissecting leiomyoma of the uterus. The Sternberg tumor. Am J Surg Pathol 1996;20:1455-1461.

4. Kim MJ, Park YK, Cho JH. Cotyledonoid dissecting leiomyoma of the uterus: a case report and review of the literature. J Korean Med Sci 2002;17:840-844.

5. Cheuk W, Chan JK, Liu JY. Cotyledonoid leiomyoma: a benign uterine tumor with alarming gross appearance. Arch Pathol Lab Med 2002;126:210-213.

6. Clement PB, Young RH, Scully RE. Diffuse, perinodular, and other patterns of hydropic degeneration within and adjacent to uterine leiomyomas. Problems in differential diagnosis. Am J Surg Pathol 1992;16:26-32.

7. Coad JE, Sulaiman RA, Das K, et al. Perinodular hydropic degeneration of a uterine leiomyoma: a diagnostic challenge. Hum Pathol 1997;28:249-251.

8. Ceyhan K, Simsir C, Dolen I, et al. Multinodular hydropic leiomyoma of the uterus with perinodular hydropic degeneration and extrauterine extension. Pathol Int 2002;52:540-543.

9. Dunn JS, Anderson CD, Method MW, et al. Hydropic degenerating leiomyoma presenting as pseudo-Meigs syndrome with elevated CA 125. Obstet Gynecol 1998;92:648-649.

10. Amant F, Gabriel C, Timmerman D, et al. Pseudo-Meigs' syndrome caused by a hydropic degenerating uterine leiomyoma with elevated CA 125. Gynecol Oncol 2001;83:153-157.

11. Magro G, Manusia M. Multilocular cystic epithelioid leiomyoma of the uterus with focal lymphangioma-like pattern: report of a case with immunohistochemical study. Pathol Res Pract 1998;194:49-54.

12. Scholz P, Kuhnt C. Uterus myomatosus with large cystic multilocular pseudocystic degeneration. On the differential diagnosis of uterus cysts. Zntralbl Gynakol 1991;113:157-159.

13. Juglard R, Tourrette JH, Terrier JP, et al. [Giant hydropic fibroma: a case report] J Radiol 2002;83:372-374.

14. Zaloudek C, Hendrickson MR. Mesenchymal tumors of the uterus. In: Kurman RJ, ed. Blaustein's Pathology of the Female Genital Tract, 5th ed. New York, Springer. 2002, pp 561-615.

15. Hendrickson MR, Kemson RL. Surgical pathology of the uterine corpus. In Bennington J ed. Major Problems in Pathology. Philadelphia, WB Saunders, 1980, pp 473-484.

In the depth of winter I finally learned that within me there lay an
invincible summer
--Albert Camus

Kathleen Coard, MBBS, DM (Path), and Joseph Plummer, MBBS, DM, (Surg)

Department of Pathology and Department of Surgery, Radiology Anaesthetics & Intensive Care, The University of the West Indies, Mona, Kingston, Jamaica.

Reprint requests to Dr. Kathleen Coard, Department of Pathology, The University of the West Indies, Kingston 7, Jamaica. Email: [e-mail]

Accepted August 10, 2006.

RELATED ARTICLE: Key Points

* Leiomyomas are the most common tumors of the uterus.

* Most leiomyomas are easily identified, with typical gross and microscopic appearances.

* A number of less common gross and microscopic variants exist.

* Although rare, these tumors may become massive with extensive cystic degeneration.

* Unusual leiomyomas must be considered in the differential diagnosis of intra-abdominal masses in all female patients.