Unusual sites

J. S. P. YUEN*, P. K. H. CHOW*, H. N. KOONG*, J .M. S. HO# and R. GIRIJA#
*Department of General Surgery and #Department of Pathology, Singapore General Hospital, Singapore

Introduction

Case 1

Extra-pelvic endometriosis in the thorax or umbilical hernia is rare. We report a case of thoracic endometriosis presenting with isolated chest pain and a case of endometriosis in an umbilical hernial sac mimicking incarceration. The clinical course and management of the patients and a literature review of these two unusual sites of endometriosis are discussed.

Endometriosis is the presence of ectopic endometrial tissue that responds to hormonal stimulation. It is found in 8-15% of all menstruating women. Most cases are pelvic endometriosis presenting to gynaecologists. On the other hand, endometriosis usually presents to the general surgeons with deposits at extragonadal, extra-pelvic sites or in the skin. While these cases are more commonly associated with incisional abdominal scars, endometriosis in the thorax and umbilical hernia are very rare sites of occurrence of the disease.1 We report on two cases of unusual endometriosis which presented as diagnostic problems to the general surgeon.

A 45-year-old Chinese woman, presented with a 5-year history of recurrent right lower chest wall pain during menstruation. The symptom usually occurred one day after the onset of menstruation and lasted for 1-2 days during each menstrual cycle. She described the pain as constant, extending from the right subcostal margin to the right parasternal area. She had a dilatation and curettage for menorrhagia, which showed the presence of active chronic cervicitis with squamous metaplasia and mild focal active chronic endometritis. She later underwent a total hysterectomy with conservation of the ovaries for uterine leiomyoma, 9 months prior to this presentation. Interestingly, she became asymptomatic for 4 months after the hysterectomy only to recur monthly, thereafter. Clinically, no abnormality was detected on physical examination; in particular, no mass was palpable in the abdomen and the chest wall.

A computerised tomography (CT) scan of the thorax revealed an irregular shaped 40 mm paracardial mass abutting against the anterior chest wall, with possible involvement of the liver through the diaphragm (Figure 1). There were no signs of pneumothorax, haemothorax or pneumomediastinum.

Computerised tomography of the pelvis failed to demonstrate any pelvic pathology. To further characterise the lesion, a magnetic resonance imaging (MRI) scan of the thorax and abdomen was carried out. This showed a 44 mm vascular mass with the epicentre in the peri-cardial fat transgressing the right hemi-diaphragm and extending into the peritoneal cavity and abutting on the left lobe of the liver (Figure 2). The MRI appearance of the lesion was not typical of endometriosis and this raised the possibility of a soft tissue sarcoma arising from the diaphragm.

Through a composite right infra-mammary paramedian incision, a 40 x 40 mm intra-thoracic mass was found to be adherent to the anterior chest wall involving the 6th and 7th ribs, the pericardium and diaphragm. There was transdiaphragmatic extension to segment four of the liver. En-bloc resection of the lesion with the right 6th and 7th ribs, including the involved pericardium, diaphragm and liver was carried out. Primary closure of the chest wall, diaphragm and abdominal wall was performed.

Histological examination of the specimen showed the presence of florid endometriosis with fibrosis, chronic inflammation, old haemorrhage and some chronic inflammation in the endometrial stroma (Figure 3). There was no evidence of malignancy. The ribs and liver were not involved but dense fibrous adhesions were present. Postoperatively, she made an uneventful recovery and was discharged well on the 6th post-operative day. On follow up, she was well and symptom-free.

Figure 1: Computerised tomography (CT) scan of the thorax showed an irregular shaped 40 mm paracardial mass abutting against the anterior chest wall and the liver

A 43-year-old Chinese woman, presented with a 2-week history of central abdominal pain localising to the umbilicus which has been increasing in severity. She otherwise has no symptoms suggestive of pelvic endometriosis. She had a lower midline incision scar for caeserian section about 9 years ago. On examination, she had a tender, irreducible umbilical hernia with skin discolouration. There were no other lump or masses in the abdomen or the midline scar.

The initial impression was that of an incarcerated umbilical hernia with possible bowel strangulation. An emergency surgical exploration performed on the same day of admission showed the presence of an umbilical hernia with a small piece of infarcted pre-peritoneal fat attached at its apex to a purplish lesion beneath the umbilicus. The discoloured umbilical skin was excised together with the infarcted preperitoneal fat. A Mayo repair of the abdominal wall defect was performed.

Histology of the specimen showed sections of skin with an endometriotic focus within the lower dermis. There were dilated glands forming cysts lined by columnar epithelium with surrounding stromal cells. Post-operatively, she made a quick recovery without any complications. On further questioning, she revealed that the symptoms came on during her menses for a few months prior to presentation. On followup, she was well, asymptomatic and with no evidence of concurrent pelvic endometriosis.

Figure 2: Magnetic resonance image of the thorax and abdomen (sagittal view) showed a vascular mass with epicentre in the pericardial fat

Figure 3 (a) : Histological examination of the specimen showed the presence of florid endometriotic glands and stroma (A) within the fibrous tissue of the chest wall (B).

Figure 3 (b): Histology section showing the presence of endometriosis glands in subcutaneous tissue in the chest wall

The first case report of thoracic endometriosis was described in 1953 in a patient with a haemothorax.² Since then, about 110 cases have been described in the literature. The usual clinical presentations are pneumothorax, haemothorax, haemoptysis and pulmonary nodules. Our patient’s presentation was atypical as her only complaint was isolated cyclical chest pain and there has been only one other case with this unique presentation reported in the literature.³ Compared with other sites of extra-pelvic endometriosis, where less than 50% had cyclical symptoms, 90% of patients with thoracic endometriosis had onset of symptoms within 24-48 hours after commencement of menstruation.4 However, diagnosis in this patient was not easy, given its unusual clinical presentation, and a MRI finding of an anterior mediastinal vascular lesion suspicious of a malignant soft tissue tumour. In light of the MRI findings and her atypical presentation, surgical treatment was offered with a view to establishing the histological diagnosis, excluding malignancy and providing definitive treatment.

Surgical treatment of thoracic endometriosis has been shown to be more effective than current medical treatments which are only partially effective and associated with high rates of recurrence of symptoms.4 Medically, oral contraceptives, progesterone and Danazol have been used to suppress the ectopic endometrium by blocking the oestrogen stimulation from the ovary. For patients who present with pneumothorax or haemothorax, chemical or surgical pleurodesis has been shown to be superior to hormonal therapy in preventing recurrence.⁴ Moreover, total hysterectomy and bilateral salpingo-oophorectomy (THBSO), as a definitive surgical treatment for thoracic endometriosis, may not be effective if oestrogen replacement therapy is subsequently prescribed. The latter can reactivate the dormant thoracic endometrial tissue resulting in recurrence of disease.⁵

Cutaneous endometriosis presenting to general surgeons is often mistaken for a suture granuloma, abscess, cyst, lipoma or incisional hernia.⁶ Umbilical involvement is estimated to represent 0.5-1% of all sites of the disease. Cases of umbilical endometriosis are well described in the literature over the last 30 years with more than 30 cases having been reported. However, to the best of our knowledge, there have been only two cases of endometriosis reported arising within an umbilical hernia. Endometriosis at this site is not only rare; it can present diagnostic pitfalls to the general surgeon, as this case illustrates. Thus, it should be considered in the differential diagnosis of all pre-menopausal women presenting with umbilical swellings.

For some patients, there may be no relationship between the swelling and menstruation, as alluded to above. The diagnosis is often made incidentally by histologic examination after surgical exploration and excision of the lesion.⁷ The fact that up to 50% of these affected women may have concomitant pelvic endometriosis, further pre-operative diagnostic investigations, in a non-emergent setting, is advisable; gynaecological referral should be made early and better preoperative planning can be carried out. This is important as concurrent pelvic endometriosis needs to be treated to prevent reseeding of endometrial tissue from the pelvis. We suggest that in suspected cases, where emergency surgical exploration is not warranted, MRI is recommended as the best investigation. This modality of imaging has been shown to be useful for delineating the size and location of extra-pelvic endometriosis and in excluding intra-abdominal extension of the disease.⁸

Extra-pelvic endometriosis in the thorax and umbilical hernial sac is rare and may present as diagnostic dilemas to the general surgeon. Delays in diagnosis are usually due to the failure to associate the patient’s symptoms with menses and the absence of a cyclical feature of symptoms in some patients. It should be considered in the differential diagnosis of all pre-menopausal women presenting with nondescript chest and abdominal pain.

1. Nirula R, Greaney GC. Incisional endometriosis: an underappreciated diagnosis in general surgery. J Am Coll Surg 2000; 190: 404-7
2. Barnes J. Endometriosis of the pleura and ovaries. J Obstet Gynecol Brit Emp 1953; 60: 823-4
3. Horsfield K. Catamenial pleural pain. Eur Respir J 1989; 2: 1013-4
4. Joseph J, Sahn SA. Thoracic endometriosis syndrome: New observations from an analysis of 110 cases. Am J Med 1996; 100: 164-70
5. Joseph J, Reed CE, Sahn SA. Thoracic endometriosis: recurrence following hysterectomy with bilateral salpingo-oophorectomy and successful treatment with talc pleurodesis. Chest 1994; 106: 1894-6
6. Seydel AS, Sickel JZ, Warner ED, Sax HC. Extra-pelvic endometriosis: diagnosis and treatment. Am J Surg 1996; 171: 239-41
7. Singh KK, Lessells AM, Adam DJ, Jordan C, Miles WF, MacIntyre IM, Greig JD. Presentations of endometriosis to general surgeons: a 10-year experience. Br J Surg 1995; 82: 1349-51
8. Yu CY, Perez-Reyes M, Brown JJ, Borrello JA. MR appearance of umbilical endometriosis. J Comput Assist Tomogr 1994; 18: 269-71

Copyright date: 30th May 2001
Correspondence: P.K.H. Chow, Department of General Surgery, Singapore General Hospital, Singapore 169608

Unusual sites (thorax and umbilical hernial sac) of endometriosis