Journal of Postgraduate Medicine Medknow Publications and Staff Society of Seth GS Medical College and KEM Hospital, Mumbai, India ISSN: 0022-3859 EISSN: 0972-2823 Vol. 47, Num. 4, 2001, pp. 281

Journal of Postgraduate Medicine, Vol. 47, Issue 4, 2001 pp.281

Letter to the Editor

Heterotopic Uterine Cartilage

Code Number: jp01082

We report herewith a rare case of heterotopic uterine cartilage. A 45-year-old gravida six, para six female underwent hysterectomy for complaints of menorrhagia. The uterus showed a 2cm circumscribed translucent nodule located in the endometrial lining just above the uterine isthmus (Figure). The nodule could be shelled out from the adjacent tissue. Microscopy revealed a lobule of benign hyaline cartilage positioned between the endometrial lining and the myometrium. There was a cleavage plane between the cartilage and adjacent tissue. However, the cartilage edges focally showed presence of endometrial stromal cells. There was no inflammation or tumour and no other tissue was identified. A diagnosis of benign heterotopic uterine cartilage was made.

Heterotopia means the occurrence of mature tissues at an abnormal location, and one of the postulated mechanisms for its occurrence is metaplasia. The multipotential cells present in normal endometrial stroma can show metaplastic transformation into a variety of elements including cartilage.(1) Such cartilaginous metaplasia usually follows trauma secondary to childbirth. We feel that the history of multiparity in our case supports the concept of metaplasia. In fact, Roth and Taylor have described cases of heterotopic uterine cartilage in which they demonstrated accumulation of acid mucopolusaccharide material similar to cartilaginous matrix in the adjacent endometrial stroma.(2)

Heterotopic uterine cartilage of metaplastic origin may occur as solitary or multiple foci, and may be located in the endometrium or even in the stroma of an endometrial polyp.(1) The lesion may be an incidental finding at hysterectomy. However, menorrhagia may occur if cartilage is located close to the endometrium as was observed in our case. Sometimes cervical lesions may be palpable as hard nodules.

Other mechanisms proposed for uterine cartilage formation include hypercalcaemia and hyperoestrinism. Dystrophic calcification and cartilage formation may be secondary to chronic inflammation as in pyometra.(3) Another interesting mechanism is iatrogenic implantation of foetal tissues including cartilage into the uterine wall following dilatation and curettage.(4)

Cartilage is a well-known feature of uterine neoplasms such as malignant mixed mullerian tumour. It is to be noted that in addition to cartilage, areas of high grade tumor with epithelial and stromal elements will be seen in this neoplasm. However, serious diagnostic problems may arise if isolated non tumour cartilage as described above is encountered in endometrial curettings and misinterpreted as a component of this neoplasm.(2) Hence correlation with clinical setting and careful and adequate microscopic examination is necessary for proper assessment of significance of uterine cartilage.

References

1. Scully RE. Smooth muscle differentiation in genital tract disorders. Arch Pathol Lab Med 1981; 105:505-507. MEDLINE
2. Roth E, Taylor HB. Heterotopic cartilage in the uterus. Obstet Gynecol 1966; 27:838-844.
3. Ganem KJ, Parsons L, Friedel GH. Endometrial ossification. Am J Obstet Gynecol 1962; 83:1592-1594.
4. Tyagi SP, Saxena K, Rizvi R, Langley FA. Foetal remnants in the uterus and their relation to other uterine heterotopia. Histopathology 1979; 3:339-345. MEDLINE

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