Ann Thorac Surg 2002;74:2172-2174
© 2002 The Society of Thoracic Surgeons
Case report
Accessory spleniculi in the right hemithorax
Lognathen Balacumaraswami, FRCSa*,
Mark Yeatman, FRCSa,
Arup Kumar Ghosh, FRCSa,
Christopher Collins, MRCPathb,
Christopher P. Forrester-Wood, FRCSa
a Department of Cardiothoracic Surgery, Bristol Royal Infirmary, Bristol, United Kingdom
b Department of Histopathology, Bristol Royal Infirmary, Bristol, United Kingdom
Accepted for publication April 1, 2002.
* Address reprint requests to Dr Balacumaraswami, Level 06 Thoracic Office, Bristol Royal Infirmary, Bristol BS2 8HW, UK United Kingdom.
e-mail: bala1log{at}hotmail.com
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Abstract
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Accessory spleniculi are present in the thoracic cavity without a history of trauma due to anomalies in the development of spleen. We report the case of a 62-year-old woman with hereditary spherocytosis and previous splenectomy with an incidental mass on a chest radiograph and an indeterminate diagnosis on needle biopsy. The probable sequence of embryological events that may explain the anatomic presence of splenic tissue in the thorax is discussed.
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Introduction
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Accessory spleniculi are present in the thoracic cavity without a history of trauma due to anomalies in the development of spleen. Intrathoracic splenic tissue was excised in a patient with hereditary spherocytosis and previous splenectomy. The probable sequence of embryological events that may explain the anatomic presence of splenic tissue in the thorax is discussed.
A case is presented of an incidentally found right paraspinal accessory spleen in a 62-year-old woman with a history of hereditary spherocytosis and prior splenectomy as a child (Fig 1).
Thoracic splenosis is a well-described phenomenon but typically occurs in the left hemithorax as a result of traumatic injury. This patient had no history of trauma. We could find no similar case reported in the literature. Physical examination showed bilateral chronic leg ulcers that had persisted despite twice-performed skin grafting and was otherwise unremarkable. Preoperative blood tests showed a hemoglobin of 9.3 gm/dL, leukocyte count of 25.7 x 109/L, platelet count 1,199 x 109/L, creatinine 75 µmol/L, and alkaline phosphatase 98 U/L. The computed tomography scan of the thorax showed the presence of a solid homogenous mass in the right paraspinal region attached to the posterior wall but free from the mediastinum and the diaphragm (Fig 2).
There was no evidence of mediastinal lymphadenopathy. There was no evidence of any other congenital malformations in the patient.
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Fig 2. Computed tomography scan of thorax showing a solid homogenous mass attached to the posterior chest wall but free from the mediastinum.
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We decided to opt for an open thoracotomy for both diagnostic and therapeutic purposes. Through a right lateral thoracotomy approach along the eighth intercostal space, ellipsoid encapsulated bluish firm masses were found in the right paravertebral gutter, not adherent to the chest wall: one measuring 10 cm in diameter, a second one measuring 6 cm in diameter, and a third measuring 4 cm in diameter (Fig 3).
They were excised, and histopathology of the masses showed tissue composed of prominent splenic red pulp with scattered and inconspicuous lymphoid follicles. There were very prominent extramedullary hemopoiesis together with hemosiderin deposit and evidence of erythrophagocytosis. The changes were typical of the splenomegaly of hemolytic anemia. The intercostal vessels provided the blood supply. She made an uneventful postoperative recovery and was discharged home on the 7th postoperative day.
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Comment
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Spleniculi are well-described embryological remnants of the migration of mesenchymal cells into the dorsal mesogastrium in the 5th week of life present in association with most of the viscera of the abdomen [1]. Thoracic splenosis is due to the presence of intrathoracic splenic tissue as a result of traumatic autotransplantation attributed to diaphragmatic injury [2]. In patients who have idiopathic thrombocytopenic purpura or hereditary spherocytosis who have undergone splenectomy, growth of previously unrecognised accessory splenic tissue has been known to occur [3, 4]. However, splenic tissue that is present as an embryological phenomenon in the thoracic cavity is not previously described.
In the 5th week of life, coelomic epithelium of the midline dorsal mesogastrium invades the mesenchyme in several adjoining areas of the dorsal mesogastrium to form the primordial spleen. The rotation of the dorsal mesogastrium to the left occurs approximately at the same time as the primordial splenic cell development. During the early stages of development of the diaphragm, pleuroperitoneal folds project from the coelomic cavity and extend in the medial and ventral directions to fuse with the mesentry of the esophagus and septum transversum at the end of the 7th week [5].
Hence, between the 5th and 7th week of embryological development, primordial splenic cells may migrate into the pleural cavity through the incomplete pleuroperitoneal folds before the fusion of the latter with the esophageal mesentery and the septum transversum, which would explain the presence of accessory splenic tissue in the right hemithorax.
In conclusion, in patients with hereditary spherocytosis presenting with an intrathoracic mass who have previously undergone splenectomy, the diagnosis of accessory splenic tissue should be considered even in the absence of a history of trauma.
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References
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- William P.L., Warwick R., Dyson M., et al. Gray’s anatomy, 37th ed New York: Churchill Livingstone, 1989:328-339.
- O’Connor J.V., Brown C.C., Thomas J.K., et al. Thoracic splenosis. Ann Thorac Surg 1998;66:552-553.[Abstract/Free Full Text]
- Rivero E, Monari J, Marquez D, et al. Bazo accesorio. Hipertrofia compensadora post esplenectomia. Presentacion de un caso. Gen 1995;49:153–6
- Walters D.N., Roberts J.L., Votaw M. Accessory splenectomy in the management of recurrent immune thrombocytopenic purpura. American Surgeon 1998;64:1077-1078.[Medline]
- Sadler T.W. Langman’s medical embryology, 7th ed Baltimore, MD: Williams and Wilkins, 1995:247-251.
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Abstract
Introduction
