Illustrated review of the embryology and development of the facial region, part 2: Late development of the fetal face and changes in the face from the newborn to adulthood.

The later embryogenesis of the fetal face and the alteration in the facial structure from birth to adulthood have been reviewed. Part 3 of the review will address the molecular mechanisms that are responsible for the changes described in parts 1 and 2.

Illustrated review of the embryology and development of the facial region, part 3: an overview of the molecular interactions responsible for facial development.

SUMMARY: Parts 1 and 2 of this review discussed the complex morphogenesis of the face. However, the molecular processes that drive the morphology of the face were not addressed. Part 3 of this review will present an overview of the genes and their products that have been implicated in the developing face.

Anatomy and pathology of the masticator space.

OBJECTIVE: This article reviews and illustrates the anatomy and pathology of the masticator space (MS). BACKGROUND: Pathology of the masticator space includes inflammatory conditions, vascular lesions, and tumours. Intrinsic tumours of this space can be benign and malignant, and they may arise from the mandibular ramus, the third division of the trigeminal nerve, or the mastication muscles. Malignant tumours may appear well defined and confined by the masticator fascia, without imaging signs of aggressive extension into neighbouring soft tissues. Secondary invasion of the masticator space can also occur with tumours of the nasopharynx, oropharynx, oral cavity, and parotid glands. Perineural tumour spread (PNS), especially along the trigeminal nerve, can also occur with masticator space malignancies. CONCLUSION: Masses of the MS are difficult to evaluate clinically, and computed tomographic (CT) and magnetic resonance (MR) images are essential for the diagnosis and characterisation of these lesions. Malignant tumours may appear well defined and confined by the fascia. Thus, when a mass is identified, a biopsy should be done promptly. PNS may occur in tumours involving the MS and its recognition on imaging studies is essential to plan the appropriate treatment. TEACHING POINTS: • Differentiating between intrinsic and extrinsic lesions is essential to the differential diagnosis • Infections of the MS may cross the fascia and mimic neoplasms on imaging studies • Malignant tumours may show no aggressive signs, such as bone erosion or violation of the fascia • Perineural spread (PNS) is often clinically silent and frequently missed at imaging and leads to tumour recurrence.

Illustrated review of the embryology and development of the facial region, part 1: Early face and lateral nasal cavities.

The early embryological development of the face has been reviewed. One repeating theme to note is the serial closing and then the re-opening of a space. This is seen in the separation of the nasal and oral cavities, the nostrils, and in part 2 the developing eyelids fusing and then re-opening. Part 2 will discuss the further facial development as well as the changes in facial bone appearance after birth.

Parotid gland atrophy in patients with chronic trigeminal nerve denervation.

BACKGROUND AND PURPOSE: Trigeminal nerve injury or dysfunction is associated with denervation atrophy of muscles innervated by the mandibular branch of the trigeminal nerve. The purpose of our study was to evaluate the association between chronic CN V denervation and parotid gland atrophy. MATERIALS AND METHODS: Twenty-six patients with chronic masticator muscle atrophy were retrospectively identified and evaluated for the presence of ipsilateral parotid gland atrophy. Twenty-six age-matched control subjects with no clinical or imaging evidence of chronic masticator space atrophy were also identified. Segmentation of the parotid gland was performed to calculate a parotid asymmetry index. The Fisher exact test and t test were respectively used to determine the correlation between parotid gland atrophy and ipsilateral masticator muscle atrophy and to evaluate any difference in the size of the involved parotid gland when compared with that in the control subjects. RESULTS: Ipsilateral parotid gland atrophy was seen in 9/26 (42.8%) patients with fatty replacement of the masticator group of muscles, suggesting a correlation between parotid gland atrophy and CN V denervation (P<.001). The parotid asymmetry index was significantly different in patients with CN V denervation (0.59±0.25) compared with control subjects (0.92±0.03) (P<.001). CONCLUSIONS: Ipsilateral parotid gland atrophy can accompany chronic CN V denervation change, and its clinical significance remains to be determined.

Solución del caso 42. Linfoma multifocal facial y orbitario / Solution to Case 42. Multifocal facial and orbital lymphoma

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The CT appearance of a corneal melt: report of 2 cases.

When the cornea of the eye dissolves, most commonly secondary to infection or trauma, the ventral wall of the anterior chamber of the eye is no longer supported and thus bulges forward, enlarging the anterior chamber volume. This is referred to as a corneal melt, and it has a unique CT appearance that has not been previously described.

A rare case of Reidel thyroiditis with associated vocal cord paralysis: CT and MR imaging features.

Reidel thyroiditis is extremely rare and not only involves the thyroid gland but usually extends to neighboring structures in the neck. A rare complication of this disease is entrapment of the recurrent laryngeal nerve causing a vocal cord paralysis. In fact, to our knowledge, this is likely the only benign thyroid disease to cause such a paralysis. We present a case of a 57-year-old woman with Reidel thyroiditis and a recurrent laryngeal nerve paralysis. The CT and MR imaging features are presented as well as a brief review of this disease.

Solución del caso 12. Síndrome del seno silente / No disponible

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Unilateral hypopharyngitis, cellulitis, and a multinodular goiter: a triad of findings suggestive of acute suppurative thyroiditis.

Acute suppurative thyroiditis is an uncommon disorder, which has been associated with pre-existing thyroid disease, especially a multinodular goiter. We describe a case of a woman who presented clinically with an acute inflammatory condition of the neck. On CT examination, she had a triad of a multinodular goiter, a unilateral hypopharyngitis, and a surrounding cellulitis. We suggest that the constellation of these imaging findings should alert the radiologist to the diagnosis of acute thyroiditis.

The significance and management of incidental [18F]fluorodeoxyglucose-positron-emission tomography uptake in the thyroid gland in patients with cancer.

BACKGROUND AND PURPOSE: Incidental positron-emission tomography (PET) uptake in the thyroid bed represents a diagnostic dilemma. Currently, there is no consensus regarding the significance of this finding or the most appropriate approach to management. The purpose of this study was to determine the significance of incidental fluorodeoxyglucose (FDG) uptake in the thyroid gland on [(18)F]FDG-positron-emission tomography (FDG-PET/CT) in patients being initially staged for lymphomas and/or cancers other than of thyroid origin. MATERIALS AND METHODS: A retrospective review was conducted on patients who were incidentally found to have focal FDG uptake in the thyroid bed on initial staging for cancer. Patient records were assessed for age, sex, clinical presentation, standard uptake values (SUV(max)), on FDG-PET/CT, and CT findings in those patients undergoing FDG-PET/CT, fine-needle aspiration (FNA) cytology, and surgical pathologic examination. RESULTS: Thirty patients were identified with incidental FDG-PET uptake in the thyroid bed from 630 studies performed for evaluation of cancer between March 2004 and June 2006. Complete records were available for 18 patients (6 men, 12 women). Five (27.8%) of 18 patients with incidental focal FDG-PET/CT uptake in the thyroid gland demonstrated papillary thyroid carcinoma on final pathologic findings. The mean and SD of SUV(max) was 3.0 +/- 1.8 (range, 1.1-7.4) overall, 2.9 +/- 1.6 (range, 1.1-6.8) in the patients without malignant growth, and 3.4 +/- 2.6 (range, 1.1-7.4) in the 5 patients with papillary thyroid carcinoma. No statistical difference in SUV(max) was noted between patients with papillary thyroid carcinoma and patients with benign pathologic findings (P = .63). CONCLUSIONS: Incidental FDG-PET uptake in the thyroid gland in patients with cancer of nonthyroidal origin is associated with a 27.8% risk for well-differentiated thyroid carcinoma; however, there seems to be no correlation between intensity of FDG uptake and the risk for a malignant process.

3D CT evaluation of common crus aplasia.

Aplasia of the common crus is an uncommon congenital anomaly. We present the case of a patient with common crus aplasia and discuss the relevant embryology and the role of 3D CT in evaluation of this rare congenital anomaly.

Crista galli pneumatization is an extension of the adjacent frontal sinuses.

BACKGROUND AND PURPOSE: The crista galli is part of the ethmoid bone and, as such, it could be expected that aeration of the crista would come from ethmoid cells. After observing crista pneumatization from the frontal sinuses in several cases, we undertook this study to establish how often crista galli pneumatization came from the frontal sinuses rather than from the ethmoid complex. MATERIALS AND METHODS: Two hundred consecutive CT scans of the paranasal sinuses were studied in adult patients to obtain the incidence of crista galli pneumatization and the cell of origin for this phenomenon. A second group of 132 children, 0-7 years of age, was studied to see if any crista galli pneumatization occurred before frontal sinus development. A third group of 79 children, 7-12 years of age, was also studied to see when crista pneumatization occurred in children whose frontal sinuses had already extended into the squamosal portion of the frontal bone. RESULTS: Of the 200 adult cases, there were 26 patients (13%) with crista galli pneumatization, all from either the left or right frontal sinuses. In the second group of children 0-7 years of age, there were no cases of crista pneumatization. In the third group of children 7-12 years of age, there were 4 cases of crista galli pneumatization, all from well-developed frontal sinuses. CONCLUSIONS: Our study indicates that crista galli pneumatization is virtually exclusively from either the left or right frontal sinuses and not from displaced ethmoid complex cells in the frontal recess. This finding may have surgical implications when disease is present in the crista galli.

Cervical tracheal compression in a patient with achalasia: an uncommon event.

We report a case of a 79-year-old woman with long-standing achalasia that resulted in respiratory stridor and dyspnea. She was evaluated for tracheal compression with use of CT on inspiration and expiration. Airway obstruction and acute respiratory distress secondary to achalasia have been reported in the clinical literature. The importance of recognizing these rare manifestations is crucial for the appropriate treatment of these patients. In this patient, the CT evaluation of tracheal compression provided useful information on the degree of narrowing caused by the dilated esophagus.

Interfrontal sinus septal cell: a cause of obstructing inflammation and mucoceles.

BACKGROUND AND PURPOSE: Recent interest in the origin and complications associated with frontal intersinus septal cells prompted us to review our material looking for cases of the uncommon occurrence of a mucocele developing within such a cell. The purpose of this article was to present the imaging findings on 4 cases of mucoceles arising within surgically proven frontal intersinus septal cells. MATERIALS AND METHODS: A retrospective review of the case material in our department of otolaryngology since 2000 was made looking for cases of patients with surgically proven frontal intersinus septal cell mucoceles. Institutional review board approval for the review was obtained. Four cases were identified that also had CT and/or MR imaging studies. Examples of 4 additional classic frontal sinus mucoceles and 3 anterior ethmoid mucoceles were also identified for comparison. RESULTS: All 4 of the cases of frontal intersinus septal cell mucoceles had an expanded midline frontal sinus cell, which thinned the posterior and/or anterior frontal sinus tables. The classic frontal sinus mucoceles were either to the left or right side, and any table thinning was off midline. The ethmoid mucoceles were clearly centered below the frontal sinuses. CONCLUSIONS: The rare occurrence of a frontal intersinus septal mucocele can be diagnosed on CT and MR imaging studies, because its appearance in the midline is clearly distinct from the more common classic frontal sinus mucoceles that develop within the left or right frontal sinus proper. Distinction is also routinely made from large anterior ethmoid mucoceles.

The frontal intersinus septal air cell: a new hypothesis of its origin.

BACKGROUND AND PURPOSE: Air cells are often seen within the frontal intersinus septum. These cells have traditionally been thought to arise from displaced ethmoid cells from the frontal recess. This study explores the possibility that such cells may actually be diverticula from the frontal sinuses themselves and not of a direct ethmoid origin. MATERIALS AND METHODS: A prospective study of 200 consecutive CT scans in the coronal and axial planes was performed on patients without a history of recent trauma. The images were interpreted independently by a radiologist and an otolaryngologist. The CT studies were evaluated for the presence of a central intersinus septal air cell. If such a cell was identified, it was further classified as either being completely isolated from both frontal sinuses by a bony rim or as a communicating diverticulum from one of the frontal sinuses. If a central cell was present, it was also assessed for how much of the height of the intersinus septum it involved (lower one-half or full height). RESULTS: There was a complete concordance of the results between the 2 observers. An intersinus septal air cell was seen in 61 (30.5%) of the 200 cases, and 85.3% of these cells were clearly seen to communicate anteromedially with either one of the frontal sinuses or both frontal sinuses (3 cases). In 9 (4.5%) of the 200 cases, the central cell had no demonstrable connection to either frontal sinus. Of the 61 cases with a central cell, 55 (90.16%) of the cells occupied the full height of the septum, and 6 (9.84%) only involved the lower half of the septum. CONCLUSION: Contrary to the present convention that frontal intersinus septal cells originate as displaced ethmoid cells from the frontal recess, we found that most such cells are actually diverticula from the frontal sinuses themselves.

A rare spontaneous osteosarcoma of the calvarium in a patient with long-standing fibrous dysplasia: CT and MR findings.

A 52-year-old man with long-standing craniofacial polyostotic fibrous dysplasia (FD) and no history of prior radiation therapy developed a spontaneous right temporal bone osteosarcoma. Such spontaneous sarcomatous degeneration of FD is rare, particularly in the calvarium/skull, where, to our knowledge, only six prior cases have been reported in the literature. We report this case because it is a rare entity with well-documented CT and MR images, and to emphasize the importance of depicting imaging features of sarcomatous degeneration among the complex imaging findings of FD.

Severe diffuse systemic amyloidosis with involvement of the pharynx, larynx, and trachea: CT and MR findings.

Amyloidosis is a term applied to a diverse group of disorders that share the deposition of amyloid protein in various extracellular tissues. Systemic amyloidosis may involve almost any organ system in the body including regions in the head and neck; however, pharyngeal involvement is rare, with only 12 cases having been previously reported. Ten of these cases were localized disease, and only 2 cases were systemic amyloidosis. We present the case of a patient with severe diffuse systemic amyloidosis with extensive involvement of the pharynx, larynx, trachea, lungs, eyelids, and breasts. We also review the imaging characteristics and pertinent literature.