Some non-small cell carcinomas of the lung can express TTF1 and p40 in the same tumor cells. This event has been described in only six cases prior to this one, and only in one other female. It is an extraordinary event that appears as a new entity yet to be defined. The case presented is a woman with a non-small cell lung carcinoma with diffuse coexpression of TTF1 and p40 in the same cells.

Most lung carcinomas are subtyped by their morphologies; however, immunohistochemistry is usually performed when it is difficult to determine. The most reliable antibodies for distinguishing lung adenocarcinoma from squamous cell carcinoma are thyroid transcription factor-1 (TTF-1) and p40 (ΔNp63). In general, these markers are mutually exclusive in their expression of lung primary carcinoma; however, a few cases of non-small cell lung carcinoma (NSCLC) with coexpression of both markers have been reported. Examining a tissue microarray of 229 squamous cell carcinomas and 346 adenocarcinomas, we found one case of NSCLC with coexpression of TTF-1 and p40. Herein, we present a 71-year-old man, who had a mass lesion in the left lung apex. A transbronchial lung biopsy was performed, revealing NSCLC. He underwent left upper segmentectomy and lymph node dissection. Macroscopically, the mass showed a white-to-tan solid tumor on the cut surface. Microscopically, the tumor was composed of polygonal tumor cells which had round and vesicular nuclei with prominent nucleoli. They had an abundant amount of cytoplasm, which was slightly eosinophilic or amphophilic. Multinucleated cells with atypical nuclear features were observed to be scattered in some areas. Multifocal necrosis and hemorrhage were also noted. Distinct squamous features and obvious glandular features were absent. Immunohistochemically, the most tumor cells were coexpressed positive for both TTF-1 and p40. In our study, NSCLC with TTF-1 and p40 coexpression is rare; therefore, it is necessary to obtain further data and examine similar cases to establish more precise definitions and clinicopathological features.

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UNASSIGNED: Sebaceous carcinoma (SC) of the submandibular gland is extremely rare. Owing to the low morbidity and nonspecific clinical manifestations, diagnosis is commonly delayed, which increases metastasis and mortality. To date, there have been five reported cases of SC of the submandibular gland. Here, we present a new case and review the relevant literature.
UNASSIGNED: A 36-year-old woman presented with an enlarged left submandibular gland. Clinical features included a non-tender solitary nodular mass with normal overlying skin. There were no special findings on computed tomography or ultrasound examination except for a swollen mass in the left submandibular gland. The patient underwent surgical resection. Pathological examination confirmed the diagnosis of SC with nerve infiltration. Immunohistochemical examination of this case showed positive staining for P63, P40, CK7, CK8/18, MLH1, MSH2, MSH6, and PMS2. The specimen was negative for androgen receptor, CEA, S-100, CK5/6, SOX-10, SOX-11, SMA, and GCDFP-15. The KI-67 labeling index was determined to be 15%. PAS and anti-epithelial membrane antigen were positive in partial area. The patient is still undergoing follow-up, and no metastasis or recurrence has been observed for 2 months.
UNASSIGNED: This case highlighted the fact that despite its rarity, SC should be considered as a differential diagnosis for masses located in the head and face. Early and accurate diagnosis, followed by wide surgical excision, has a favorable prognosis. Therefore, clinicians should be familiar with the clinical and pathological features of this disease.

P40 and thyroid transcription factor-1 (TTF-1) dual expression in non-small cell lung cancer (NSCLC) is a rare occurrence. However, the presence of EML4-ALK and PIK3CA gene mutations in this type of cancer is unknown. The present study describes the case of a 38-year-old male patient who had never smoked. A 4.5-cm mass adjacent to his right upper mediastinum was detected by a computed tomography (CT) scan of the chest. Biopsy of the level four lymph nodes in the right mediastinum revealed microscopic morphological features typical of high-grade NSCLC. Immunohistochemical findings resembled those reported previously for several cases of NSCLC with the dual expression of P40 and TTF-1 markers. In addition, echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit a (PIK3CA) gene mutations were detected using high-throughput next-generation sequencing. To the best of our knowledge, this is the first report of NSCLC with the expression of P40 and TTF-1 as well as EML4-ALK and PIK3CA gene mutations. The presence of this type of tumor should be considered in patients with NSCLC who have never smoked and may have unique clinicopathological features.

Background: Hyalinizing clear cell carcinomas of tracheobronchial origin are very rare salivary gland type tumors accounting for less than 1% of lung tumors with only 13 cases reported to date. Their radiological features, morphological spectrum, and molecular features are not well described. Aim: To perform a clinicopathological analysis of primary pulmonary hyalinizing clear cell carcinomas. Method: A retrospective search of primary pulmonary hyalinizing clear cell carcinomas was conducted from authors\' institutions and the clinicopathological features including details of molecular testing were analyzed. Results: Five primary pulmonary hyalinizing clear cell carcinomas were identified. The mean patient age at diagnosis was 48.2 years (range: 33-64 years). Three patients were women. All patients were nonsmokers and 3 were symptomatic; 2 were detected incidentally during health screening. The tumors were located in the main lobar bronchi ranging from 1.3 to 4.9 cm in maximum dimension. Microscopy showed cords and nests of at least, focally clear tumor cells. Mucin cysts lacking goblet cells were seen. All tumors were uniformly positive for p40, p63, AE1/AE3, keratin 7, and epithelial membrane antigen but negative for TTF1, KIT, neuroendocrine markers, and other myoepithelial markers. All cases showed Ewing sarcoma breakpoint region 1 (EWSR1) gene rearrangement. Perineural invasion and lymph node metastases were detected in patient 5. Two patients with available follow-up data were recurrence-free until 4 years (patient 1) and 9 months (patient 5) after resection. Conclusion: The present series adds to the scant available literature on primary pulmonary hyalinizing clear cell carcinomas highlighting the characteristic histomorphology, immunoprofiles, and benign outcomes of these rare tumors.

Pleomorphic adenoma is the most common kind of major tumor of the major and minor salivary organs. Although pleomorphic adenoma is a benign tumor, it has a high chance of recurrence and malignancy. In the literature, lower rates of repetitive pleomorphic adenoma of the sense of taste have been detailed while the palate is a common location for an intraoral pleomorphic adenoma. Recurring tumors have been associated with a high risk of malignancy, and surgical excision is the basic treatment option for recurrent adenomas. Revision surgery is quite challenging and has never been standardized. We report a rare case of recurrent pleomorphic adenoma of the palate that occurred 7.5 years after primary ablation.

Adamantinoma-like Ewing sarcoma is a rare variant of Ewing sarcoma with histologic and immunohistochemical evidence of squamous differentiation. This variant most commonly occurs in the head and neck region with a few cases reported in the long bones of the limbs. It may be associated with poorer clinical outcome and could pose a diagnostic challenge, particularly if it occurs in older patients or as a metastatic lesion. We present a case of Ewing sarcoma in the metatarsal of an 11-year-old boy that manifested adamantinoma-like morphology after neoadjuvant chemotherapy. Chemotherapy has been reported to induce neuronal maturation and rhabdoid morphology in cases of Ewing sarcoma, but no reports of treatment-induced squamous differentiation with P40/P63 expression have been demonstrated. This is also the first documented case treated with a pedicled osteocutaneous fibular transfer in a metatarsal malignancy, which is usually treated by either ray or below-knee amputation.

UNASSIGNED: The 2011 WHO Classification for lung adenocarcinoma enlightened the need for a wise use of immunohistochemistry to preserve tissue for both diagnosis and molecular studies. The current recommendation is to use a panel comprising TTF1 and p40 to classify tumors with no clear squamous or glandular differentiation as many studies have showed the higher specificity of p40 over p63 as marker of squamous differentiation. However, the co-expression of both markers opens a new scenario with subsequent classification and potentially treatment issues.
UNASSIGNED: We report a case of a non-small lung cell carcinoma (NSCLC) with coexistent expression of TTF1 and p40 in the same tumour cells. To our knowledge, this peculiar immunohistochemical profile is very rare, and thus a review of the clinical and molecular features including molecular variances of the tumour was performed. Review of the pertinent literature was also carried out.
UNASSIGNED: Two additional articles describing unusual cases of NSCLC with coexistent expression of TTF1 and p40 were found and compared to our case. Interestingly, they all carried out aberrant mutation in TP53 oncogene and were of advance stage.
UNASSIGNED: The positivity for both \"squamous\" and \"adenocarcinomatous\" markers and mutations of TP53 could be the expression of a not fully recognized variant of NSCLC with possible implications for classification, diagnosis and therapy.

BACKGROUND: Primary gastric squamous cell carcinoma (SCC) is a very rare disease. The origin of this tumor remains unclear, although there are some hypotheses. A 60-year-old man consulted a previous physician complaining of upper abdominal pain. Esophagogastroduodenoscopy revealed type 2 gastric cancer, and the patient was referred to our hospital. After close examination, the patient was diagnosed as cStage IIA gastric adenocarcinoma, and distal gastrectomy was performed. Histochemical studies showed typical findings of SCC, and the tumor was surrounded by intestinal metaplasia. Immunohistochemical examination was positive for cytokeratin (CK) 5/6 and caudal-type homeobox protein 2 (CDX2) and negative for p63/p40.
CONCLUSIONS: The results of immunostaining for CK5/6 supported that this tumor was SCC, but the question why p63/p40 were negative and CDX2 was positive still remained. Concerning about the origin of p63/p40 and CDX2, it was suggested that the tumor cells were not derived from ectopic squamous epithelium but from intestinal metaplasia. And tumor cells looked like homogeneous and squamous metaplasia was not observed. These findings supported the idea that these tumor cells arose from stem cells in the intestinal metaplasia of the stomach.