Niche Specific Microbiota-Dependent and Independent Bone Loss around Dental Implants and Teeth.

Oral mucosal homeostasis is achieved by complex immunologic mechanisms, orchestrating host immunity to adapt to the physiologic functions of the various specialized niches in the oral cavity. Dental implants introduce a novel mucosal niche to the immune system to deal with. Nevertheless, the immune mechanisms engaged toward implants and whether they have broader effects are not well defined. Using a murine model, we found an accumulation of neutrophils and RANKL-expressing T and B lymphocytes in the implant-surrounding mucosa, accompanied by local bone loss. Surprisingly, the presence of implants had an impact on remote periodontal sites, as elevated inflammation and accelerated bone loss were detected in intact distant teeth. This was due to microbial dysbiosis induced by the implants, since antibiotic treatment prevented bone loss around teeth. However, antibiotic treatment failed to prevent the loss of implant-supporting bone, highlighting the distinct mechanisms mediating bone loss at each site. Further analysis revealed that implants induced chronic lymphocyte activation and increased mRNA expression of IFN-α and accumulation of IFN-α-producing plasmacytoid dendritic cells, which we previously reported as bone-destructive immune responses. Collectively, this study demonstrates that implants have a strong and broad impact on oral mucosal homeostasis, inducing periodontal bone loss in a niche-specific manner that is both microbiota dependent and independent.

Significance and management of thyroid lesions in lymph nodes as an incidental finding during neck dissection.

BACKGROUND: The incidental discovery of thyroid lesions in lymph nodes during a lymph node dissection performed for a separate primary head and neck tumor is an unusual clinical entity. Its discovery has led to controversy regarding its significance and management. METHODS: We identified five patients over the years 1991-1999 with this finding. All five patients were subsequently treated with a total thyroidectomy and a level VI lymph node dissection. RESULTS: Pathological examination revealed three papillary carcinomas and level VI lymph node metastases in the two patients who had carcinoma in their thyroid glands. All five patients are presently free of their primary and thyroid disease on follow-up examinations. CONCLUSIONS: These patients should be addressed with additional work-up and surgery if metastatic thyroid cancer is documented in the lymph node. We offer a diagnostic algorithm that may aid in further work-up and treatment in these unusual cases.

Histomorphometric analysis of human sphenoid and maxillary mucosa: measurement of relative density of goblet cells and basal cells.

The majority of malignant tumors of the paranasal sinus are squamous cell carcinomas and arise most commonly in the maxillary sinus, and less commonly in the nasal cavity and other sinuses. Glandular tumors (nonsquamous tumors) develop much less commonly and have a different distribution within the paranasal sinuses. The majority of adenomatous tumors arise from the surface mucosa and submucosal seromucinous glands. Attempts to explain tumorigenesis propose that the distribution of these tumors is based on the variance of different cell types among the sinuses. The authors used morphometric analysis to measure the relative density of goblet cells and basal cells from maxillary, and sphenoid sinus specimens. Surgical specimens of normal maxillary and sphenoid mucosa were retrieved from 5 and 10 patients, respectively. All specimens were stained with periodic acid-Schiff stain. The area of goblet and basal cells in five representative areas of each specimen were measured and compared to the total cross-sectional area of the mucosa, giving a relative density of each cell type. The average goblet cell density was 31.19% (SD +/- 10.27%) in maxillary tissue and 33.25% (SD +/- 20.80%) in sphenoid tissue. Student's t-test showed no statistically significant difference in goblet cell density between the two sinuses. The average basal cell density was 9.53% (SD +/- 0.87%) for maxillary tissue and 10.91% (SD +/- 1.91%) for sphenoid tissue. Again, no statistically significant difference between the two sinuses existed. In conclusion, there is no clearly detectable difference in the histologic composition of these two paranasal sinuses to explain the different incidence of glandular tumors, and other etiologic factors must be considered in explaining tumorigenesis at these sites.

Ramification amplification: a novel isothermal DNA amplification method.

We have developed a novel isothermal DNA amplification method with an amplification mechanism quite different from conventional PCR. This method uses a specially designed circular probe (C-probe) in which the 3' and 5' ends are brought together in juxtaposition by hybridization to a target. The two ends are then covalently linked by a T4 DNA ligase in a target-dependent manner, producing a closed DNA circle. In the presence of an excess of primers (forward and reverse primers), a DNA polymerase extends the bound forward primer along the C-probe and displaces the downstream strand, generating a multimeric single-stranded DNA (ssDNA), analogous to the "rolling circle" replication of bacteriophages in vivo. This multimeric ssDNA then serves as a template for multiple reverse primers to hybridize, extend, and displace downstream DNA, generating a large ramified (branching) DNA complex. This ramification process continues until all ssDNAs become double-stranded, resulting in an exponential amplification that distinguishes itself from the previously described nonexponential rolling circle amplification. In this report, we prove the principle of ramification amplification. By using a unique bacteriophage DNA polymerase, Ø29 DNA Polymerase, that has an intrinsic high processivity, we are able to achieve significant amplification within 1 hour at 35 degrees C. In addition, we applied this technique for in situ detection of Epstein-Barr viral sequences in Raji cells.

Mucoepidermoid carcinoma: a clinicopathologic study of 80 patients with special reference to histological grading.

We sought to review our experience with salivary mucoepidermoid carcinoma (MEC) over two decades to confirm the validity and reproducibility of histologic grading and to investigate MIB-1 index as a prognosticator. Diagnosis was confirmed on 80 cases, and chart review or patient contact was achieved for 48 patients, with follow-up from 5 to 240 months (median 36 months). Immunohistochemistry with citrate antigen retrieval for MIB-1 was performed on a subset of cases. Kaplan-Meier survival curves were generated for each stage, site, and grade according to our proposed grading system. To address the issue of grading reproducibility, 20 slides were circulated among five observers, without prior discussion; slides were categorized as low-, intermediate-, or high-grade according to one's "own" criteria, and then according to the AFIP criteria proposed by Goode et al.10 Weighted kappa (kappa) estimates were obtained to describe the extent of agreement between pairs of rating. The Wilcoxon signed rank test or the Friedman test as appropriate tested variation across ratings. There was no gender predominance and a wide age range (15-86 years, median 49 years). The two most common sites were parotid and palate. All grade 1 MECs presented as Stage I tumors, and no failures were seen for this category. The local disease failure rates at 75 months for grades 2 and 3 MEC were 30% and 70%, respectively. Tumor grade, stage, and negative margin status all correlated with disease-free survival (DFS) (p = 0.0091, 0.0002, and 0.048, respectively). The MIB index was not found to be predictive of grade. Regarding the reproducibility of grading, the interobserver variation for pathologists using their "own" grading, as expressed by the kappa value, ranged from good agreement (kappa = 0.79) to poor (kappa = 0.27) (average kappa = 0.49). A somewhat better interobserver reproducibility was achieved when the pathologists utilized the standardized AFIP criteria (average kappa = 0.61, range 0.38-0.77). This greater agreement was also reflected in the Friedman test (statistical testing of intraobserver equality), which indicated significant differences in using one's own grading systems (p = 0.0001) but not in applying the AFIP "standardized" grading (p = 0.33). When one's own grading was compared with the AFIP grading, there were 100 pairs of grading "events," with 46 disagreements/100 pairs. For 98% of disagreements, the AFIP grading "downgraded" tumors. This led us to reanalyze a subset of 31 patients for DFS versus grade, for our grading schema compared with the AFIP grading. Although statistical significance was not achieved for this subset, the log rank value revealed a trend for our grading (p = 0.0993) compared with the Goode schema (p = 0.2493). This clinicopathologic analysis confirms the predictive value of tumor staging and three-tiered histologic grading. Our grading exercise confirms that there is significant grading disparity for MEC, even among experienced ENT/oral pathologists. The improved reproducibility obtained when the weighted AFIP criteria were used speaks to the need for an accepted and easily reproducible system. However, these proposed criteria have a tendency to downgrade MEC. Therefore, the addition of other criteria (such as vascular invasion, pattern of tumor infiltration [i.e., small islands and individual cells vs cohesive islands]) is necessary. We propose a modified grading schema, which enhances predictability and provides much needed reproducibility.

Sinonasal undifferentiated carcinoma: immunohistochemical profile and lack of EBV association.

The role of Epstein-Barr virus (EBV) in the development of sinonasal undifferentiated carcinoma (SNUC) remains unresolved. Reports of EBV-positivity in SNUC may reflect inclusion of lymphoepithelioma-like carcinomas within this group. In addition, SNUC have been incompletely characterized immunohistochemically, and their undifferentiated appearance often requires such ancillary studies to aid in their distinction from other high-grade neoplasms. To address these two issues, 25 cases of SNUC diagnosed between the years 1983 and 1999 were selected from our files. EBER in situ hybridization (ISH) was performed on the paraffin-embedded tissue by using 3H-labeled EBER-1 RNA probes. Neoplasms with sufficient tissue (22 of 25) were evaluated immunohistochemically for Ki-67, p53, chromogranin, synaptophysin, placental alkaline phosphatase (PLAP), CD99, carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), neuron-specific enolase (NSE), and latent membrane protein-1 (LMP-1). The median patient age was 58 years (range, 20-81 years), with a male-to-female ratio of approximately 3:1. The most common tumor location was the nasal cavity (18 cases), followed by the ethmoid and maxillary sinuses. Median survival was 18 months. All 25 tumors were negative for EBER-I by ISH. Ki-67 was negative in one case, 1+ in nine, 2+ in six, 3+ in five, and 4+ in one. P53 was negative in nine, 1+ in five, 2+ in two, 3+ in none, and 4+ in six. CD99 expression was strongly positive in 3 of 22 (14%) and completely negative in the remainder. Variably intense focal staining for EMA was present in 4 of 22 (18%). NSE faintly stained 4 of 22 (18%). Chromogranin, synaptophysin, PLAP, CEA, and LMP-1 were negative (0 of 22). Our results suggest that EBV does not play a role in the development of SNUC. Strict histologic criteria are necessary to avoid confusion with lymphoepithelioma-like carcinoma or other high-grade malignancies in this region. The finding of occasional CD99-positive cases adds SNUC to the growing list of CD99-positive neoplasms.

Lymphatic malformation: predictive factors for recurrence.

OBJECTIVE: Although lymphatic malformations are often found to be well circumscribed when surgery is undertaken in early childhood, complete surgical excision can be difficult when the lesion is infiltrative. This study retrospectively evaluates these patients in an attempt to identify prognostic factors that may predict recurrence. STUDY DESIGN AND SETTING: A retrospective chart review was conducted covering the years 1991 to 1998. Seventeen patients were identified having undergone 32 surgical resections of tumors described as lymphatic malformations. Data abstracted from the charts included the site of the lesion, surgical and histologic assessment of encapsulation, and status at follow-up examination. RESULTS: Six of 17 patients developed a recurrence after surgery. Correlation between recurrence and histologic or operative impressions of encapsulation was significant by chi(2) analysis (P<0.01). CONCLUSION: On the basis of the findings of this case series, lymphatic malformations that are found to be nonencapsulated and infiltrative by intraoperative or histologic assessment are more likely to recur.

A clinicopathological study of sinonasal neuroendocrine carcinoma and sinonasal undifferentiated carcinoma.

OBJECTIVE: Sinonasal undifferentiated carcinoma (SNUC) and sinonasal neuroendocrine carcinoma (SNEC) are relatively newly recognized, rare entities requiring further clinicopathological analysis to advance our understanding and determine prognostic distinctions between them. STUDY DESIGN: Retrospective chart review. METHODS: Cases were retrieved from the Copath system. One patient was seen in consultation from an outside institution. Histological and immunohistochemical findings, patient demographics, treatment regimens, and outcomes were analyzed and compared. RESULTS: Ten patients (7 men, 3 women) ranging in age from 17 to 58 years (mean age, 44.7 y) were included. Four patients were classified with SNEC, six as having SNUC. The predominant site was the superior nasal cavity or ethmoids (seven cases), followed by the maxilla (four cases). Disease in four patients was clinically staged as N1 (three with SNUC, one with SNEC), and in six patients as NO (three with SNEC, three with SNUC). Of the nine patients who were treated initially with surgical resection, seven received postoperative radiation therapy alone, one received postoperative radiation and chemotherapy, and one had only limited postoperative chemotherapy. One patient was treated with radiation therapy and chemotherapy alone, without surgical resection. Follow-up was obtained ranging from 6 to 108 months (mean period, 26.4 mo). Three patients died of disease 10, 14, and 41 months, respectively, after diagnosis. Three patients had persistent disease at 6, 9, and 21 months, respectively, two of them with distant metastases. Four patients were disease free after 6, 18, 31, and 108 months, respectively. CONCLUSIONS: SNUC and SNEC are both aggressive tumors, usually presenting in middle age as a nasal mass. Both tumors have the capacity to metastasize locally and distantly, and both can result in poor outcomes. This small series precludes a demographic or prognostic distinction between the two groups.

Use of the peritracheal fold in the dog tracheal transplantation model.

OBJECTIVE: To investigate the technical aspects of the canine model of human tracheal transplantation for potential application to reconstruction of extremely long tracheal defects (> 10 cm). DESIGN: In phase 1, long tracheal segments were skeletonized and pedicled with the thyroid glands, cranial thyroid arteries and veins, and internal jugular vein branches. The segments were elevated completely, attached to the vascular pedicle only, and replaced with primary tracheal anastomoses. In phase 2, long segments were elevated along with a diffuse soft tissue "blanket" that envelops the trachea and thyroid glands. Because this study was designed to primarily address, in situ, tracheal perfusion territories of a cranially located vascular pedicle, microvascular anastomoses were not conducted. SUBJECTS: Two small-bodied beagles (10-15 kg) and 5 large-bodied mixed-breed dogs (20-30 kg) were humanely killed 2 to 41 days after surgery, and anatomic and histological analyses were conducted. RESULTS: Unlike that of humans, the thyroid gland complex of dogs is not intimately associated with the trachea but is conjoined with a peritracheal soft tissue "fold." Within this fold, blood is transmitted to the trachea via a diffuse, segmental vascular plexus. In phase 1, pronounced tracheal necrosis occurred within 2 to 5 days. In phase 2, extremely long tracheal segments (10-12 cm), based only on a cranially located pedicle, were still viable at 2 to 6 weeks. CONCLUSIONS: Preservation of the "peritracheal fold" in the dog model of tracheal transplantation is critical to the onset and maintenance of vascular perfusion in a long tracheal segment. Furthermore, the use of large-bodied dogs is necessary to provide for a usable venous efflux component.

Upper aerodigestive tract liposarcoma: report on four cases and literature review.

OBJECTIVE: To report on the clinical behavior, histopathology, treatment, and prognosis of laryngeal, hypopharyngeal, and cervical esophageal liposarcomas. STUDY DESIGN: Retrospective reviews of pathology files and hospital records at a tertiary care hospital and a retrospective search of the English-language literature. METHODS: Cases of upper aerodigestive tract (UADT) liposarcoma with adequate histopathologic documentation and clinical information were included for review. RESULTS: Four cases of UADT liposarcomas were identified. The literature review revealed 26 cases of laryngeal liposarcomas, 7 cases of hypopharyngeal liposarcomas, and 6 cases of esophageal liposarcomas: the mean age at presentation was 55.8 years, the male:female ratio was 5:1, and 60% of the patients presented with dysphagia. Eighty-six percent of tumors had low-grade histologic findings. The recurrence rate after primary resection was 50%. Recurrence correlated with surgical procedure rather than with histologic subtype; 94.7% of recurrences happened after simple excision. Distant metastases occurred in three patients; two of them died of the disease. CONCLUSIONS: The literature supports that UADT liposarcomas are rare and usually of low-grade histologic type. The rate of metastatic disease and tumor-related mortality is low. However, high recurrence rates have been noted, particularly when less radical surgery is employed.

The back door: venous-mediated metastasis into cervical lymph nodes as an alternative metastatic pathway for oropharyngeal squamous cell carcinoma.

Circulating lymphocytes may home to lymph nodes (LNs) via paracortical postcapillary venules, high-endothelial venules (HEVs) that recognize circulating lymphocytes, enabling them to migrate into nodal cortical/paracortical regions. Our goal was to find any histologic, immunohistochemical, or in vitro evidence to support the hypothesis that squamous cell carcinoma (SCC) may gain access to LNs via an alternative venolymphatic pathway. Slides from 67 neck dissections with SCC were studied. Standard criteria for lymphatic-mediated metastasis were used; criteria for evidence ofvenolymphatic metastasis were tumor nests localized to the paracortical regions, directly contiguous to HEVs but not marginal sinuses. Cases in which LN architecture was obliterated by metastases were excluded. A modified Stamper-Woodruff assay, which assesses HEV binding, incubated cell lines from oral carcinomas and lung adenocarcinomas with fresh frozen LN sections. Double-blinded cell counts were performed by two observers and analyzed by Student's t test. Immunohistochemical examination was undertaken on 19 paraffin-embedded cases with the monoclonal antibody, MoAb CD44v6, to discover whether expression of this adhesion molecule correlated with metastatic pattern. Twenty-nine cases (66%) revealed evidence only for the LN route of metastasis; 4 cases (9%) were classified as venolymphatic metastasis; 11 cases (25%) showed evidence for both pathways. The Stamper-Woodruff assay confirmed that SCC cells preferentially bound to HEV within cervical LN sections more than did adenocarcinoma cells (P = .02). Strong staining to MoAb CD44v6 was seen in 18 (95%) of 19 SCCs with a membranous pattern. Occasionally, CD44v6 highlighted tumor emboli adjacent to HEVs, but no overall correlation could be made between CD44v6 expression and pattern of spread. Tumor metastasis via lymphatic channels is the predominant mode of metastatic spread, but the venolymphatic route is a plausible alternative pathway. The preferential attachment of SCC cells to HEVs supports this theory.

Malignant melanomas of the parotid: comparison of survival for patients with metastases from known vs unknown primary tumor sites.

BACKGROUND: Malignant melanoma (MM) rarely affects the parotid, and usually this diagnosis will herald a search for a primary skin neoplasm. Occasionally, no primary tumor is ever found, raising questions regarding prognosis and the issue of primary melanoma of the parotid. OBJECTIVE: To evaluate retrospectively the clinical and histological features of MM involving the parotid in 19 patients. DATA SOURCES: Pathology and hospital files at 3 tertiary care university hospitals. STUDY SELECTION: Patients with MM within the parotid with adequate histopathologic and immunohistochemical documentation, as well as clinical information regarding patient outcome. DATA EXTRACTION: In 6 patients, no extraparotid MM was ever identified. After parotidectomy, 5 patients (including 1 patient who died of other causes) were melanoma free at a mean of 4.2 years (range, 14 months to 7.5 years). Only 1 patient died of disease after 17 months. An extraparotid primary tumor was present in 13 patients, 10 with dermal and 3 with mucosal sites. At follow-up, only 1 of these patients was disease free after 2 years. Nine patients died of melanoma after a mean of 2.6 years (range, 10 months to 5 years); the other 3 had evidence of metastatic disease at a mean of 4.3 years (range, 3-6 years). Nondermal sites of primary tumors were the nasal cavity, sclera, and conjunctiva. DATA SYNTHESIS: Patients with metastatic MM from unknown primary tumors have a longer disease-free survival than those with metastases from known primary disease. CONCLUSIONS: Although rare, MM should be considered in the differential diagnosis of parotid tumors. Unusual mucosal or ocular sites should be considered in the search for possible primary tumor sites to avoid treatment delay. These data support the idea that patients with metastatic MM from unknown primary tumors may follow a more improved course than that of patients with metastases from known primary disease.

Sialoblastoma: clinicopathological/immunohistochemical study.

Sialoblastoma is an extremely rare salivary tumor diagnosed at birth or shortly thereafter with significant variability in histologic range and clinical course, so that for an individual case it may be difficult to predict the most appropriate therapy. We detail the case of a toddler noted to have a firm 1-2-cm mass in the left cheek at 21 months. Parotidectomy was performed at 26 months, revealing a sialoblastoma; the resection margins were positive. During the next 10 months, the mass recurred or persisted, necessitating numerous procedures. The tumor was composed of basaloid cells with fine chromatin and other more mature cuboidal epithelial cells. Ductules and solid organoid nests with some tendency toward peripheral pallisading were also noted. There was no perineural invasion; necrosis initially was sparse but increased over time. The mitotic rate also increased from 6 to 7/10 high-power fields in the first resection to 20/10 high-power fields in the last resection. Nuclear pleomorphism increased with time. The MiB1 proliferative index revealed a dramatic increase in the number of labeled nuclei: from 3 cells/10 high-power fields in the first specimen to 94 cells/10 high-power fields for the last specimen. Cytokeratin accentuated the ductal structures. S-100 showed a diffuse staining pattern, with darker staining of the spindled myoepithelial cells. The Her-2-neu protein showed moderate cytoplasmic staining, whereas the p53 showed only occasional labeling of nuclei. This is the first case of sialoblastoma with evidence of increasing anaplasia based on increasing proliferative capacity. Therefore, the distinction between benign and malignant sialoblastomas may not be as well defined as previously thought. The patient's prognosis is likely to be determined by the tumor grade as well as the stage at presentation and the extent of resection.

Granular cell tumor of the parotid.

A case of granular cell tumor of the major salivary glands is presented. This tumor appeared as an expansive multinodular mass that arose from facial nerve trunks. The presenting symptoms of facial pain and paresis and the intraoperative findings of tumor adhesion to nerves led to the clinical impression of malignancy. At intraoperative consultation, the tumor resembled an acinic cell carcinoma. Pathologists should be aware that granular cell tumors may involve the major salivary glands and that it should be considered in the diagnostic differential diagnosis.

Human papillomavirus may be common within nasopharyngeal carcinoma of Caucasian Americans: investigation of Epstein-Barr virus and human papillomavirus in eastern and western nasopharyngeal carcinoma using ligation-dependent polymerase chain reaction.

BACKGROUND: Nasopharyngeal carcinoma (NPC), particularly those tumors endemic to the Far East, commonly harbor Epstein-Barr virus (EBV), thought to serve as an important oncogenic promoter. Human papillomavirus (HPV) is associated with a proportion of upper aerodigestive tract carcinomas. We hypothesized that HPV might also contribute to the pathogenesis of NPC, and we queried whether geographic and racial distinctions may be identified between NPC of the Far East versus those diagnosed in Caucasian American patients with regard to the interrelationship of histologic subtype and viral infection. MATERIALS AND METHODS: Formalin-fixed paraffin-embedded tissue (FFPET) from 30 patients (6 Caucasian Americans, 1 Chinese American, 14 and 9 patients from Korea and China, respectively) were studied using the ligation-dependent polymerase chain reaction (LD-PCR). These cases were histologically classified according to the World Health Organization (WHO) schema for NPC. Consensus target probes complementary to the L1 region of over 30 HPV types, as well as target probes complementary to EBER-1 (EBV-related nontranslated latency-associated RNA), were used to amplify target sequences. RESULTS: Seven of 30 NPC (23%) contained HPV sequences. There were 6 Caucasian American patients with NPC; 3 cases (50%) were HPV positive (HPV+). Two of these Caucasian Americans had WHO type I tumors: one was HPV+ and EBV negative (EBV-) and the other was HPV-/EBV+. The remaining Caucasian American NPCs were WHO-II/III tumors which tested as follows: two were coinfected with HPV and EBV, the other two contained EBER but not HPV sequences. The single Oriental American patient had a WHO-III NPC which was HPV-/EBV+. Of the Eastern NPC patients, 4 (1 WHO-I, 3 WHO-II/III) of 23 (17%) NPCs contained HPV sequences as well as EBV. Conclusion. Human papillomavirus appears to be uncommonly (17%) associated with NPC in patients from the Far East and was detected more often (50%) in NPC from American Caucasian patients. Some of these tumors conformed to our perceptions and expectations of NPC (eg, WHO-I tumors being EBV-/HPV+ and WHO-III tumors being EBV+/HPV-), but other tumors did not conform to these expectations (eg, WHO-III NPC occasionally harboring both HPV and EBV). There appears to be a broad profile in the relationship between HPV, EBV, and NPC histologic subtype. Unfortunately, the number of American Caucasian cases studied are too small to allow for strong conclusions.

Benign intratracheal thyroid: a possible cause for preoperative overstaging.

We report a rare case of intratracheal thyroid ectopia in the setting of papillary thyroid carcinoma, resulting in the preoperative clinical impression of an aggressive, high-stage tumor. A 24-year-old opera singer presented with complaints of a gagging or choking sensation. The results of computed tomography revealed a mass in the left thyroid lobe with multiple small calcifications consistent with papillary thyroid carcinoma as well as a soft tissue mass in the adjacent left tracheal lumen thought to be direct invasion by the thyroid tumor. A total thyroidectomy was performed including excision of half of the first and second tracheal cartilages and the lower portion of the hemicricoid cartilage. The final histological findings revealed that the intratracheal component was composed of benign thyroid tissue and strands of benign thyrocytes coursed through the first tracheal membrane. Intratracheal thyroid ectopia is a rare symptomatic occurrence with a striking female predisposition. We have identified 23 cases of intratracheal thyroid ectopia from the literature. They occur most often at the level of the cricoid, usually posteriorly with a slight predisposition for the left side. Continuity between the intratracheal component and the thyroid lobe may be seen. Clinicians and pathologists must be aware of this entity to avoid mistaking it for evidence of thyroid invasion by a malignant neoplasm.