Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma: case report and literature review

Primary Nasopharyngeal Papillary Adenocarcinoma: Report of 2 Cases and Review of the Literature

The primary nasopharyngeal papillary adenocarcinoma (NPPA) is extremely rare which accounts for less than 0.48% of all malignant neoplasms in the nasopharynx. The clinical features, diagnosis, and treatment of NPPA have not been well described. We present 2 patients with NPPA that were treated with total endoscopic resection and radiotherapy at Vietnam National Cancer Hospital. Through these cases and reviewing of the literature, we provide deeper understanding of NPPA to highlight clinical pathological characteristics and the optimal treatment strategy for patients with pathologically confirmed NPPA. Our 2 cases were successfully treated and remained disease-free 4 years after treatment. The NPPA was usually an indolent tumor with polypoid appearance and slow growth rate and has a good prognosis. Surgical excision, including endonasal endoscopic excision with or without adjuvant radiotherapy, was most effective with a localized and operable tumor.

Radiological features of thyroid-like low-grade nasopharyngeal papillary adenocarcinoma: case series and systematic review

PURPOSE

To comprehensively summarize the clinical data and CT/MRI characteristics of thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA).

METHODS

Twenty-seven lesions from 25 study articles identified through a systematic review and three lesions from our institution associated with TL-LGNPPA were evaluated.

RESULTS

The mean age of the patients at diagnosis was 35.7 years, and the male-to-female ratio was nearly half. The chief complaint was nasal obstruction, followed by epistaxis. All patients underwent excision. None of the patients had neck nodes or distant metastases. All patients survived with no locoregional/distant recurrence during 3-93 months of follow-up. All lesions were located at the posterior edge of the nasal septum, attached to the nasopharyngeal parietal wall, and showed no laterality. The mean lesion diameter was 1.7 cm. The margins of lesions were well-defined and lobulated, followed by well-defined smooth margins. None of lesions were associated with parapharyngeal space or skull base destruction. All lesions were iso- and low-density on non-contrast CT. Adjacent skull base sclerosis was detected in 63.6% of lesions. High signal intensity on T2-weighted imaging and mostly iso-signal intensity on T1-weighted imaging compared to muscle tissue. Most lesions were heterogeneous and exhibited moderate contrast enhancement. Relatively large lesions (≥1.4 cm) tended to be more lobulated than smooth margins compared to relatively small lesions (<1.4 cm) (p = 0.016).

CONCLUSION

We summarized the clinical and radiological features of TL-LGNPPA to facilitate accurate diagnosis and appropriate management.

Immunohistochemical characteristics of thyroid-like low-grade nasopharyngeal papillary adenocarcinoma: A case report and review

BACKGROUND

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is a rare nasopharyngeal malignant tumor that is easy to misdiagnose. Immunohistochemistry plays an indispensable role in distinguishing TL-LGNPPA from other malignancies. However, there is no article to summarize the immunohistochemical characteristics of TL-LGNPPA. Herein, we report a case of TL-LGNPPA and present the immunohistochemical results reported in the Chinese literature.

METHODS

An electronic search of the CNKI (China National Knowledge Infrastructure) database was performed. From our literature survey, 53 cases of TL-LGNPPA (including the case described in this report) have been identified in China. We summarize the Chinese literature's clinical characteristics, immunohistochemical results, treatments, and prognosis of 53 cases.

RESULTS

Based on our literature survey, 53 cases of TL-LGNPPA (including the case described in this report) have been reported in China. We found TL-LGNPPA and papillary thyroid carcinoma were positive for TTF-1 and CK19. TL-LGNPPA was negative for TG and PAX-8, whereas papillary thyroid carcinoma was positive for TG and PAX-8. However, negative expression of TTF-1 and positive expression of TG were also found in some TL-LGNPPA cases. Our literature survey found that all TL-LGNPPA cases were negative for PAX-8.Therefore, we suggest that simultaneous immunohistochemical determination of TTF-1 and CK19, as well as TG and PAX-8, can increase the diagnostic accuracy of TL-LGNPPA.

CONCLUSION

The 4th edition of the World Health Organization Classification of Head and Neck Tumors (WHO-HNT) indicates that NPPA with positive expression of cytokeratin 19 (CK19) and TTF-1 and negative expression of TG is called TL-LGNPPA.

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma: a clinicopathological and molecular study of four cases

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TLLGNPPA) is a rare nasopharyngeal carcinoma. To date, less than 60 cases of TLLGNPPA have been reported, and its clinical features and pathogenesis remain unclear. In this paper, four cases of TLLGNPPA were reported to clarify the clinicopathological and molecular features of this disease. Histopathological examination revealed that all tumors had papillary glandular arrangement, with a fibrovascular axis in the tumor stroma and focal nuclear groove. All tumors expressed pan-CK, CK7, and CK19, while TG and Pax-8 were negative, and the Ki-67 index was approximately 1-3%. The expression of TTF-1 was diffusely positive in two cases and focally positive in two cases. EBER was not expressed in four cases. Molecular testing was possible in three cases. No common driver event was noted, but unique, mutually exclusive molecular variants were found in each of the three tumors (FGFR4, PDK1, AXIN2, FOXL2, and PIK3C3), one also with copy number variants in MCL1 and STMN1. All four patients underwent surgical resection of the tumor and had no metastasis or recurrence from 7 to 60 months post-resection. Given the assertion that these tumors do not recur or metastasize in addition to their heterogeneous gene mutation spectrum, we propose that TLLGNPPA is a neoplasm with low malignant potential and should no longer to be referred to as an adenocarcinoma.

Genetic profile identification and clinicopathologic characteristics analysis of the thyroid-like low-grade nasopharyngeal papillary adenocarcinoma

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is an extremely rare malignancy bearing histomorphological similarities to papillary thyroid carcinoma with good prognosis. It's important to distinguish TL-LGNPPA from other papillary tumors including nasopharyngeal papillary adenocarcinoma (NPPA), metastatic and ectopic papillary thyroid cancer, and metastasized adenocarcinomas, etc. To date, only 48 cases of TL-LGNPPA have been reported in the English literatures. Here, we reported the genomic characteristics of additional 4 cases and reviewed other reports to clarify the clinicopathological features of this tumor. In this study, 41 mutations were detected by whole-exome sequencing, but no typical driver mutations were found. Two sample with Copy Number Variations (CNV) were found (7 q22. 17 q12), of which the segment spanned the regions of RASA4, POLR2J2, SPDYE2, CCL3, CCL4, etc. Additionally, no MSI and HLA LOH were found. To our knowledge, we are the first to reveal the genetic underpinnings of this rare tumor. The clinicopathological features of TL-LGNPPA were characterized, shedding more light on the essential difference between TL-LGNPPA with other papillary tumors.

Primary nasopharyngeal papillary adenocarcinoma: A CARE-compliant case report

RATIONALE

Primary nasopharyngeal papillary adenocarcinoma is a rare nasopharyngeal neoplasm with a good prognosis and a low propensity for regional recurrence. To date, only few cases of primary nasopharyngeal papillary adenocarcinoma have been reported in the literature.

PATIENT CONCERNS

A 24-year-old female patient presented with intermittent hemoptysis and blood tinge nasal discharge.

DIAGNOSIS

An exophytic and pedunculated mass over the roof of the nasopharynx was found on nasopharyngoscope. Biopsy was done and the pathology confirmed well-differentiated primary nasopharyngeal papillary adenocarcinoma, strongly positive for CK7, and transcription termination factor 1; but negative for thyroglobulin. The final diagnosis was primary nasopharyngeal papillary adenocarcinoma, well-differentiated, pT1N0M0, stage I.

INTERVENTIONS

The patient underwent excision of nasopharyngeal tumor under sinuscopic assistance.

OUTCOMES

: No local recurrence or distant metastasis was noted during the 6 months of follow-up.

LESSONS

We aim at highlighting the importance of a thorough differential diagnosis of nasopharyngeal tumor. Further investigation is still needed for providing evidence to standardize the treatment protocol.

Immunohistochemically detectable thyroglobulin expression in extrathyroidal cancer is 100% specific for thyroidal tumor origin

Thyroglobulin is a secreted 660 kDa glycoprotein produced by thyroid follicular cells used in diagnostic pathology to secure or exclude a thyroidal origin of metastases of unknown primary tumors. This study was performed to estimate specificity of thyroglobulin immunohistochemistry. 9974 tumor samples from 109 different tumor types and subtypes as well as 608 samples of 76 different normal tissue types were analyzed by immunohistochemistry in a tissue microarray format. Thyroglobulin was strongly expressed in all normal thyroid samples but not in any other normal tissues. Thyroglobulin immunostaining was detected in 99.1% of 106 thyroid adenomas, 98.1% of 364 papillary, 95.2% of 147 follicular, and 7.5% of 40 anaplastic thyroid cancers. Twelve of 15 thyroid samples that were thyroglobulin negative on TMAs showed at least a weak focal thyroglobulin positivity in corresponding large sections, suggesting higher sensitivity of large section analysis. Thyroglobulin positivity in one diffuse large B-cell lymphoma of the thyroid, one chondrosarcoma metastasis to the thyroid, and 42.4% of 92 medullary thyroid cancers was considered to be caused by diffusion of thyroidal colloid from destroyed or even intact adjacent follicles. Thyroglobulin positivity was, however, not seen in 6403 extrathyroidal tumors from 104 different tumor types and subtypes. Our data demonstrate a complete specificity of positive thyroglobulin immunostaining for thyroid origin in tumor tissues obtained from extrathyroidal locations. However, for all tumors located within the thyroid, false positivity can occur as a result of tissue contamination by thyroglobulin rich thyroid colloid from adjacent normal tissue.

Low-Grade Nasopharyngeal Papillary Adenocarcinoma: A Review of 28 Patients in a Single Institution

Purpose

Low-grade nasopharyngeal papillary adenocarcinoma (LGNPPA) is a rare nasopharyngeal tumor. This study aimed to analyze the clinical and histopathological features of the disease, and to share our experience of its treatment.

Patients and Methods

We collected demographic data, clinical symptoms, tumor location, pathological features, immunohistochemical results, treatments, and outcomes of 28 patients with pathologically confirmed LGNPPA between 2009 and 2019.

Results

The median age of the 28 patients was 41.5 years, with a female: male ratio of 1.5:1 (17 females, 11 males). The most common symptom was blood-stained rhinorrhea. The neoplasms were located on the roof of the nasopharynx (RON) in 13 patients, the posterior margin of the nasal septum (PMONP) in 12 patients, the lateral wall of the nasopharynx in one case, and both the RON and PMONP in two patients. Fourteen patients were diagnosed with thyroid-like LGNPPA. Immunohistochemically, the tumors were uniformly positive for cytokeratin 7, cytokeratin 8, vimentin, epithelial membrane antigen, and pan-cytokeratin, and negative for thyroglobulin. Twenty-three patients underwent pure endoscopic surgery, three patients underwent preoperative radiotherapy, and two patients underwent radiotherapy postoperatively. All patients were alive without evidence of lymphatic or distant metastases in the follow-up period (range: 7 to 121 months). Two patients (7%, 2/28) experienced disease recurrence.

Conclusion

LGNPPA is an indolent tumor with an excellent prognosis. Endonasal endoscopic excision was an effective treatment. It is important to distinguish thyroid-like LGNPPA from metastatic papillary thyroid carcinoma because these diseases have similar microscopic features but different prognoses.

Nasopharyngeal papillary adenocarcinoma harboring a fusion of ROS1 with GOPC: A case report

RATIONALE

Nasopharyngeal papillary adenocarcinoma is a region-specific tumor originating from the nasopharyngeal surface epithelium. Owing to its rarity, more attention has been paid to its clinicopathologic features, while little effort has been made to study the gene abnormalities that drive this tumor. We describe the first case of nasopharyngeal papillary adenocarcinoma harboring a fusion of ROS1 with GOPC.

PATIENT CONCERNS

A 22-year-old female patient was diagnosed with nasopharyngeal papillary adenocarcinoma in our hospital, and she had right nasal obstruction for more than 6 months. Nasal endoscopy revealed a mass on the posterior roof of the nasopharynx.

DIAGNOSES

Immunohistochemical staining showed that the tumor cells were diffusely positive for transcription termination factor 1, vimentin, CK19, glypican-3, and CK7, and negative for melanocyte, CK5/6, CK20, P53, P63, S100, smooth muscle actin, p16, PAX8, and thyroglobulin. The Ki-67 index was approximately 5%; EBV-encoded small nuclear RNA was negative.

INTERVENTIONS

The tumor was completely excised on endoscopy with a negative surgical margin.

OUTCOMES

No sign of recurrence was observed during the 3-year follow-up period.

LESSONS

Owing to its rarity, pathologists should be aware of this unusual neoplasm to avoid misdiagnosis. Further studies are needed to further characterize the relationship between ROS1-GOPC fusion and the pathogenesis of this carcinoma and its response to tyrosine kinase inhibitors in relapsed cases.

Clinicopathological Features of Thyroid-Like Low-Grade Nasopharyngeal Papillary Adenocarcinoma: A Case Report and Review of the Literature

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is an extremely rare neoplasm of the nasopharynx. Accordingly, its clinical and pathological characteristics are not well-known. We report a case of TL-LGNPPA and review the relevant literature on TL-LGNPPA. A 38-year-old Japanese woman presented with a history of nasal obstruction that had persisted for 1 month after symptoms of a common cold (e.g., low-grade fever, sore throat, and fatigue). A pedunculated tumor of ~20 mm in diameter was found on the posterior edge of the nasal septum. The tumor was endoscopically resected. Based on careful histopathological and immunohistochemical examinations, it was diagnosed as TL-LGNPPA. At 5 years after surgery, the patient remained disease-free. TL-LGNPPA has a very good prognosis, and complete resection with a sufficient safety margin is recommended as the first-line treatment. The morphological characteristics and immunohistochemical findings, especially TTF-1 positivity and thyroglobulin negativity, are important for the diagnosis.

Clinicopathologic Characteristics of Thyroid-like Low-grade Nasopharyngeal Papillary Adenocarcinoma: A Case Report

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is an extremely rare neoplasm. It morphologically resembles papillary thyroid carcinoma and is immunochemically positive for thyroid transcription factor 1. Herein, we reported a case of TL-LGNPPA in a female patient of 35 years old. She felt pharyngeal foreign body sensation of unknown cause and subsequently developed dyspnea after activities. Nasopharyngeal plain computerized tomography showed no abnormalities, but laryngoscopy showed a peanut-sized smooth neoplasm with a pedicel at the posterior edge of the nasal septum. The mass was completely resected by nasopharyngoscopy. Histologic examination showed the tumor was composed of papillary configuration and tubular glands; each papilla was covered with cuboidal or columnar epithelial cells; tubular architecture and spindle cell component were also observed; some tumor cells had psammoma bodies. Immunohistochemically, tumor cells were positive for CKpan, CK7, CK19, VIM, and thyroid transcription factor 1, but negative for thyroglobulin, CK20, S-100, P63, P40, smooth muscle actin, CDX-2, and glial fibrillary acidic protein. This patient was diagnosed with TL-LGNPPA and followed up for 16 months, and metastasis and recurrence were not observed.

Biphasic Thyroid-Like Low-Grade Nasopharyngeal Papillary Adenocarcinoma with a Prominent Spindle Cell Component: A Case Report

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TLLG-NPPA) is a distinctly rare malignancy of the nasopharynx. Morphologically and immunophenotypically, TLLG-NPPA resembles papillary thyroid carcinoma (PTC) and is characterized by a papillary architecture with PTC-like nuclear features and thyroid transcription factor-1 expression. Recently, some cases of TLLG-NPPA with a spindle cell component have been reported. In this study, we report a very interesting case of biphasic TLLG-NPPA that was predominantly composed of spindle cells, with comprehensive analyses of its clinical, pathological, and immunophenotypical features. A 50-year-old woman presented with a sensation of a foreign body in the nasopharynx. Nasopharyngoscopy and computed tomography demonstrated a pedunculated mass arising from the nasopharyngeal roof. Based on the clinical impression of a nasopharyngeal tumor, an excisional biopsy was performed. At low-power magnification, the nasopharyngeal mass consisted of papillary tumor tissue, the growth pattern and architecture of which resembled those of PTC. The papillae were complex and packed tightly with fibrovascular cores. At high-power magnification, each papillary structure was lined with a pseudostratified cuboidal-to-columnar epithelium. The tumor cell nuclei frequently showed a ground-glass appearance, intranuclear grooves, pseudoinclusions, and membrane thickening and irregularity, resembling the characteristic nuclear morphology of PTC. These histological features were compatible with TLLG-NPPA. Intriguingly, in between the papillary components were spindle cells that appeared very similar to the glandular epithelial cells that imperceptibly merged with the papillary component. This spindle cell component comprised two-thirds of the entire tumor volume. The nuclear morphology of the spindle cell component was similar to that of the papillary component. On immunostaining, both the papillary and spindle cell components were diffusely and strongly positive for thyroid transcription factor-1, cytokeratin 7, cytokeratin 19, vimentin, and Hector Battifora mesothelial-1. In contrast, the tumor cells tested negative for p63, p40, smooth muscle actin, S-100, cytokeratin 5/6, thyroglobulin, BRAF V600E, and Epstein–Barr virus-encoded small RNAs. Only two cases of biphasic TLLG-NPPA exhibiting a prominent spindle cell component had been reported previously in the English literature. When the pathologist receives a primary nasopharyngeal mass with the aforementioned histological features, particularly biopsy specimens with predominant spindle cells, biphasic TLLG-NPPA should be considered in the differential diagnosis. By describing its detailed clinicopathological characteristics, we anticipate that this report will expand the existing knowledge on the spindle cell component associated with TLLG-NPPA.

Primary papillary epithelial tumour of the sella: expanding the spectrum of TTF-1-positive sellar lesions

AIM

To describe four novel primary epithelial tumours of the sella with papillary architecture and Thyroid Transcription Factor 1 (TTF-1) expression.

METHODS

Paraffin-embedded tissue from the four cases and recurrence of patient 1 was investigated with haematoxylin-eosin, special histochemical stains, immunohistochemistry with a broad panel of antibodies and next-generation sequencing. The ultrastructure of one tumour was studied in tissue retrieved from paraffin.

RESULTS

The lesions occurred in three females aged 20, 26 and 42 years and a male aged 49 years. They presented with signs and symptoms secondary to pituitary stalk compression. Preoperative neuroimaging documented mixed solid and cystic, enhancing sellar masses with suprasellar extension. Histologically, the tumours showed thin papillae lined by a single layer of cytokeratin and TTF-1-positive cuboidal and cylindrical cells with mildly atypical nucleus. Next-generation sequencing performed in three cases did not identify any mutations. The main differential diagnosis included metastasis from lung or thyroid carcinoma, extraventricular choroid plexus papilloma and sellar ependymoma.

CONCLUSION

We suggest the descriptive term of primary papillary epithelial tumour of the sella (PPETS) for this entity and propose that it could represent the intracranial equivalent of thyroid-like low-grade nasopharyngeal papillary adenocarcinoma. The cell of origin of PPETS remains undetermined although the intense and ubiquitous expression of TTF-1 may suggest a derivation from the infundibulum or ventricular recess. Our study expands the spectrum of sellar TTF-1-positive tumour and challenges the view that they all derive from pituicytes.

Thyroid-Like Low-Grade Nasopharyngeal Papillary Adenocarcinoma

OBJECTIVES

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TLLGNPPA) is a relatively rare nasopharyngeal tumor. We performed morphological characterization, immunohistochemical profiling, and investigated gene mutations. We also provide clinical follow-up data and brief review of the literature.

METHODS

Immunohistochemistry was used to evaluate the expression of TTF-1, CK19, CK7, EMA, TG, Pax-8, CK5/6, S100, and Ki-67. Additionally, in situ hybridization was utilized to identify the presence of EBV. We investigated mutations in hot-spot exons of KRAS/NRAS/BRAF to rule out common mutations seen in thyroid tumors.

RESULTS

Histopathologic examination of four cases identified tumors that were mainly occupied by papillary architectures. One case had a predominantly glandular structure. The tumors expressed TTF-1 and CK19, while TG and Pax-8 were negative. S100 was moderately expressed focally in three cases.

CONCLUSIONS

While TLLGNPPA displays a morphological resemblance to papillary thyroid carcinoma (PTC), it is vital to differentiate nasopharyngeal metastasis from PTC for appropriate treatment.

Thyroid-like low-grade papillary adenocarcinoma of nasopharynx

We report a 35-year-old woman with complaints of nasal obstruction and mild post-nasal drip for 6 months. She did not improve with medical treatment. Clinical examination had no positive finding. She was evaluated with a CT scan and MRI that revealed a polypoid mass lesion in nasopharynx without any adhesion to adjacent tissue. Endoscopic examination of nasopharynx revealed an exophytic nasopharyngeal mass in anterior wall of nasopharynx that complete macroscopic transnasal endoscopic resection was performed. The histopathological examination reported thyroid-like low-grade nasopharyngeal papillary adenocarcinoma that was confirmed on immunohistochemical staining. After complete macroscopic resection of the mass, patient was regularly followed-up for 6 years and there was no evidence of recurrence. This example has the educational tips of the optimal therapeutic strategies for primary nasopharyngeal adenocarcinomas with long follow-up.

[The specific immunophenotypic features of nasopharyngeal carcinoma]

We have undertaken the retrospective analysis of the medical histories of 119 patients presenting with nasopharyngeal carcinoma (NPC) and the biopsy specimens obtained from them; the wereinvestigated with the use of the histological (staining of the micropreparations with hematoxylin and eosin) and immunehistochemical (monoclonal murine antibodies against Pan-cytokeratin, CK 5/6, EBV, CK7, CK19, p16) techniques. The study has demonstrated the presence of non-differentiated nasopharyngeal carcinoma in 97 patients, diffuse large-cell B-lymphoma in 18 ones, melanoma of the nasopharyngeal mucous membrane in 2, and nasopharyngeal rhabdosarcoma in 1 patient. The immunohistochemical study revealed co-expression of the markers of Epstein-Barr virus, Pan-cytokeratin, and CK 5/6 in the non-differentiated nasopharyngeal carcinoma .

Biphasic low-grade nasopharyngeal papillary adenocarcinoma: a case report and literature review

Background

Low-grade nasopharyngeal papillary adenocarcinoma (LGNPPA) is distinctly rare. We report a patient with a uniquely biphasic LGNPPA; additionally, we review similar tumors reported in the literature.

Case presentation

A 56-year-old man presented with an asymptomatic pedunculated tumor in the vault of the nasopharynx, at the junction of the nasal septum and the roof, which was discovered during screening for laryngeal cancer. To obtain a definitive diagnosis, the patient underwent endoscopic endonasal surgery under general anesthesia. Immunohistochemical analysis of the tumor revealed it to be an LGNPPA with a prominent spindle cell component.

Conclusion

To our knowledge, this is the fourth reported LGNPPA exhibiting a spindle cell component and the second with a prominent pathological condition. The prognosis of LGNPPA is usually excellent. Therefore, it is important for clinicians to scrutinize the lesion’s pathology to avoid unnecessary, disfiguring surgery.

Nasopharyngeal Papillary Adenocarcinoma as a Second Head and Neck Malignancy

Nasopharyngeal adenocarcinomas are rare tumours, and include neoplasms arising from the nasopharyngeal surface epithelium as well as those of minor salivary gland origin, each of which is distinct from the other. The former encompasses nasopharyngeal papillary adenocarcinoma (NPAC), also known as low grade NPAC and thyroid-like NPAC, an extremely unusual malignancy bearing histomorphological similarity to papillary thyroid carcinoma, and displaying indolent clinical behaviour. We report the case of a 41-year-old lady who developed NPAC as a second malignancy five-and-a-half years after being diagnosed and treated for a diffuse astrocytoma in the frontal lobe. In addition, we discuss the differential diagnosis, as well as raise certain pathogenetic considerations with regard to this unique neoplasm.

Thyroid-Like Intrahepatic Cholangiocarcinoma: Report of a Case and Review of the Literature

Intrahepatic cholangiocarcinoma is a relatively uncommon malignant neoplasm. We recently encountered an unusual case of intrahepatic cholangiocarcinoma that histologically resembled a thyroid carcinoma. A thorough review of the English literature revealed only 2 similar cases that have been previously reported. Immunohistochemical studies are imperative to confirm the diagnosis of cholangiocarcinoma and to exclude the possibility of metastatic thyroid carcinoma and other malignancies with thyroid-like features.

Primary thyroid-like low-grade nasopharyngeal papillary adenocarcinoma: A case report and literature review

RATIONALE

Primary thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is an extremely rare malignant nasopharyngeal tumor with features resembling papillary thyroid carcinoma including nuclear positive expression of thyroid transcription factor-1 (TTF-1).

PATIENT CONCERNS

A 64-year-old male presented with nasal bleeding and a foreign body sensation of the nasopharynx. Laryngoscopy revealed a 2.0-cm broad-based mass with a smooth surface on the posterior wall of the nasopharynx. A biopsy was obtained.

DIAGNOSES

Histopathologic examination demonstrated tumor cells arranged in both papillary and glandular architecture. The tumor cells express nuclear immunoreactivity for TTF-1. The diagnosis of TL-LGNPPA was made.

INTERVENTIONS

After the patient was diagnosed with TL-LGNPPA, he underwent complete surgical resection.

OUTCOMES

There was no recurrence or evidence of metastatic disease at the 12-month follow-up.

LESSONS

TL-LGNPPA is easy to misdiagnose as metastatic papillary thyroid carcinoma or other relative primary adenocarcinomas. It is important to have a broad differential diagnosis and know the key features of each entity because the prognosis and clinical treatment of each may differ.

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma with squamous differentiation: a novel histological finding

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is an extremely rare neoplasm originating from the nasopharyngeal surface epithelium. Histopathologically, TL-LGNPPA is characterized by cuboidal/columnar tumor cells forming papillary fronds and thyroid transcription factor-1 (TTF-1) expression resembling papillary thyroid carcinoma. To date, the recorded histological features of TL-LGNPPA have been almost uniform, and the range of histological variations in this tumor type has not been sufficiently understood. Here, we report on a 68-year-old man with TL-LGNPPA. Microscopic examination of the resected tumor revealed findings typical of papillary adenocarcinoma of this type, and moreover, this case showed scattered squamous cell foci as a hitherto unreported finding. The squamous cells showed no obvious nuclear atypia or proliferating activity, and their presence was similar to the "squamous metaplasia" of papillary thyroid carcinoma. Immunohistochemically, p40 and TTF-1 coexpression was observed in the squamous cell nuclei, indicating their origin from the glandular tumor cells of TL-LGNPPA.

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma: A case report

Thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is a rare neoplasm characterized by morphological analogy to papillary thyroid carcinoma and abnormal expression of thyroid transcription factor-1 (TTF-1). We herein report a rare case of TL-LGNPPA with a review of its clinical, morphological and immunohistochemical characteristics. The patient was a 25-year-old Japanese woman complaining of a 2-year history of fever of unknown origin. There were no remarkable physical findings and the laboratory tests, including C-reactive protein levels, were normal. Laryngoscopy, magnetic resonance imaging and fluorodeoxyglucose-positron emission tomography identified a pedunculated mass at the roof of the nasopharynx. Histologically, the tumour exhibited papillary growth of cuboidal or columnar epithelium. Tubular architecture and a spindle cell component were also observed focally. Some tumour cells exhibited intranuclear cytoplasmic inclusions. Immunohistochemically, the neoplastic cells were positive for TTF-1, cytokeratin 7 and vimentin, but were negative for thyroglobulin. The Ki-67 labelling index (MIB-1 index) reached 5% in the most concentrated spot. The patient had neither local recurrence nor distant metastasis 3 years after removal of the tumour. In conclusion, TL-LGNPPA should be included it in the differential diagnosis of fever of unknown origin.

Clinicopathological Features of Low-Grade Thyroid-like Nasopharyngeal Papillary Adenocarcinoma

PURPOSE

Primary low-grade thyroid-like papillary adenocarcinomas are extremely rare neoplasms that generally originate in the nasopharynx. Here, we describe a novel case of a 15-year-old Chinese girl who was diagnosed with low-grade thyroid-like papillary adenocarcinoma, including a brief review of the literature to reveal the clinicopathological features of low-grade thyroid-like nasopharyngeal papillary adenocarcinoma.

MATERIALS AND METHODS

Immunohistochemistry was used to evaluate the expression of pan-cytokeratin (CKpan), cytokeratin (CK) 7, thyroid transcription factor 1 (TTF-1), vimentin, epithelial membrane antigen (EMA), thyroglobulin, CD15, S100, P40, CK20, CDX-2, glial fibrillary acidic protein (GFAP), and Ki-67. Additionally, in situ hybridization investigation was utilized to identify the presence of small Epstein-Barr virus (EBV)-encoded RNA.

RESULTS

Histopathological analysis revealed florid proliferation of papillary structures lined by columnar epithelial cells with fibrovascular cores. Immunohistochemically, the neoplastic cells were positive for CKpan, CK7, TTF-1, vimentin, and EMA, but negative for thyroglobulin, CD15, S100, P40, CK20, CDX-2, and GFAP. The Ki-67-labeling index reached 5% in the most concentrated spot. In situ hybridization for EBV was negative.

CONCLUSION

Due to the distinct rarity of low-grade thyroid-like papillary adenocarcinomaswith a favorable clinical outcome, a nationwide effort to raise public awareness of this neoplasm is required.