Maldescent of the Thymus: 34 Necropsy and 10 Surgical Cases, Including 7 Thymuses Medial to the Mandible

Bale, Patricia M.; Sotelo‐Avila, Cirilo

doi:10.3109/15513819309048205

Cited by 89 publications

(59 citation statements)

References 31 publications

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“…The aberrant thymus was most often located near the thyroid gland (n ϭ 19 cases) but was also detected lower in the anterior neck (n ϭ 6 cases), higher in the anterior neck (n ϭ 8 cases), and at the left base of the skull (n ϭ 1 case). 10 The presence of thymic tissue in the retropharyngeal space in our patient is more unusual given the typical embryologic origin and descent of the thymus in the anterior neck to the mediastinum.…”

Section: Discussionmentioning

confidence: 97%

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Retropharyngeal Aberrant Thymus

Shah¹,

Lai²,

Ruchelli³

et al. 2001

Pediatrics

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ABSTRACT. Introduction. Upper airway obstruction from a retropharyngeal mass requires urgent evaluation. In children, the differential diagnosis includes infection, trauma, neoplasm, and congenital abnormalities. Aberrant cervical thymic tissue, although occasionally observed on autopsy examination, is rarely clinically significant. We present the case of an infant with respiratory distress attributed to aberrant thymic tissue located in the retropharyngeal space.Case. A 6-week-old infant was brought to the emergency department for evaluation of stridor associated with periodic episodes of cyanosis. Lateral neck radiograph revealed widening of the retropharyngeal soft tissues. The patient's symptoms did not improve with intravenous ampicillin-sulbactam. Magnetic resonance imaging (MRI) performed on the seventh day of hospitalization revealed a retropharyngeal mass that extended to the carotid space. The mass was easily resected using an intraoral approach. Microscopic examination demonstrated thymic tissue. A normal thymus was also observed in the anterior mediastinum on MRI. The patient recovered uneventfully and had no further episodes of stridor or cyanosis.Discussion. Aberrant cervical thymic tissue may be cystic or solid. Cystic cervical thymus is more common, and 6% of these patients present with symptoms of dyspnea or dysphagia. Aberrant solid cervical thymus usually presents as an asymptomatic anterior neck mass. This case is unusual in that solid thymic tissue was located in the retropharynx, a finding not previously reported in the English literature. Additionally, the patient presented in acute respiratory distress, and the diagnosis was confounded by the presence of mild laryngomalacia. In retrospect, our patient likely had symptoms of intermittent upper airway obstruction since birth. The acute respiratory distress at presentation was likely the result of laryngomalacia exacerbated by the presence of aberrant thymic tissue and a superimposed viral infection.Aberrantly located thymic tissue arises as a consequence of migrational defects during thymic embryogenesis. The thymus is a paired organ derived from the third and, to a lesser extent, fourth pharyngeal pouches. After its appearance during the sixth week of fetal life, it descends to a final position in the anterior mediastinum, adjacent to the parietal pericardium. Aberrant thymic tissue results when this tissue breaks free from the thymus as it migrates caudally. Therefore, aberrant thymic tissue may be found in any position along a line from the angle of the mandible to the sternal notch, and in the anterior mediastinum to the level of the diaphragm. In an autopsy study of 3236 children, abnormally positioned thymic tissue was found in 34 cases (1%). The aberrant thymus was most often located near the thyroid gland (n ‫؍‬ 19 cases) but was also detected lower in the anterior neck (n ‫؍‬ 6 cases), higher in the anterior neck (n ‫؍‬ 8 cases), and at the left base of the skull (n ‫؍‬ 1 case). The presence of thymic tissue in the retropharyngeal ...

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Section: Discussionmentioning

confidence: 97%

“…Twenty-four (71%) of 34 children with aberrant thymus detected at autopsy had features consistent with DiGeorge syndrome, and only 5 of the remaining 10 patients had a normal mediastinal thymus present. 10 Our patient had normal serum calcium levels postexcision and a mediastinal thymus was visualized on MRI.…”

Section: Discussionmentioning

confidence: 99%

Retropharyngeal Aberrant Thymus

Shah¹,

Lai²,

Ruchelli³

et al. 2001

Pediatrics

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“…12 Extent of abnormal differentiation of the thymus varies from agenesis to ectopic to normal. 13 The thymus was undetectable after BMT by echogram or computed tomography. However, T cells increased in peripheral blood and had characteristics of thymus-derived T cells, such as TCR ␣␤-positivity.…”

Section: Discussionmentioning

confidence: 99%

Complete-type DiGeorge syndrome treated by bone marrow transplantation

Matsumoto

Amamoto

Kondoh

et al. 1998

Bone Marrow Transplant

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Summary:BMT was carried out on a patient with DiGeorge syndrome who suffered recurrent infections after birth. At 13 months of age, 8.0 × 10 8 /kg of bone marrow nuclear cells were infused from an HLA-identical sibling using only anti-thymocyte globulin to prevent rejection. Donor DNA was not detected on microsatellite polymorphism by PCR. At 19 months of age, a second BMT from the same donor was carried out using busulfan and cyclophosphamide as conditioning. DNA examination of bone marrow showed chimerism at day 18 and complete donor origin at day 28. Seven months post-BMT, the numbers of CD3-, CD4-and CD8-positive cells were in the normal range. BMT is thus an effective therapy for DiGeorge syndrome. Keywords: DiGeorge syndrome; complete type; immunodeficiency; bone marrow transplantation DiGeorge syndrome (DGS) is characterized by dysmorphic faces, congenital heart disease, hypocalcemia and T cell dysfunction due to aplasia of the thymus. 1 Although confirmation of aplasia of the thymus is difficult, it is clinically classified as complete or incomplete; the former manifests with cellular immunodeficiency and the latter does not. 2 Therapies for the immunodeficient type of this syndrome have been fetal thymus transplantation, thymic hormone administration and bone marrow transplantation (BMT). For thymic transplantation, it is necessary to use fetal thymic tissue 3 or to use cultured thymic epithelial tissue, since it is not as easy to get donor cells. For thymic hormones such as thymosin, thymopoietin and thymulin, it is unclear what nature of thymic hormones should be used and over what time period, results have varied. 4 BMT has been attempted for DGS in seven patients 5 and two of these underwent transplantation without any pre-conditioning, with favourable results. 6,7 Here, we report a patient with complete-type DGS treated with BMT who exhibited reconstitution of T cell immunity.Correspondence: T Matsumoto, Department of Pediatrics, Nagasaki University School of Medicine, Sakamoto 1-7-1, Nagasaki 852, Japan Received 6 February 1998; accepted 8 July 1998 Case reportA boy was born at 39 weeks gestation with an Apgar score of 7. His birth weight was 3275 g. There were no special events during gestation except for polyhydramion. Family history was negative. He showed cyanosis after birth and respiratory arrest occurred at day 6 probably due to hypocalcemia, and he was referred to the National Nagasaki Central Hospital. He showed the characteristic facial features such as a hypertelorism, narrowed palpebral fissures, low set ears, deformity of both ear helices, anteverted nostrils, a shortened philtrum, micrognathia and a high arched palate. He had hypocalcemia with a low plasma level of parathyroid hormone. Chest X-ray, ultrasound and computed tomography (CT) showed no thymus-like components. Echocardiogram and cardiac catheterization revealed tetralgy of Fallot. He failed to thrive, and showed a tendency towards infection after admission, including repeated episodes of fever and continuous presence of ec...

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“…Главный признак, определяющий синдром Ди Джорджи, -гипоплазия или аплазия тимуса, характерными иммунологическими проявлениями которой являются значительное уменьшение коли-чества циркулирующих Т-лимфоцитов и снижение их пролиферативной активности. При этом тимиче-ская ткань может занимать эктопическое положение (язык, щитовидная железа, среднее ухо), но обеспе-чивать близкую к нормальному функцию [19]. Толь-ко у 0,5-1,0% детей наблюдается полное отсутствие Т-лимфоцитов и истинная аплазия тимуса.…”

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