Hodgkin lymphoma (HL) is diagnosed definitively by biopsy, and treatment is based on stage. Owing to the nature of the disease, post-treatment efficacy is determined mainly by fluorodeoxyglucose-positron emission tomography/computed tomography, and the efficacy of treatment is not confirmed by histopathology. We report a case of tongue cancer after treatment for HL, in which a post-treatment lymph node with complete remission was histopathologically confirmed by neck dissection.
The patient was a 74-year-old man who was referred to our hospital for cancer on the right side of his tongue. He had previously undergone chemotherapy for HL involving the right side of his neck and achieved complete remission. Because he had cT3N2cM0 tongue cancer, glossectomy and bilateral neck dissection were performed. Surprisingly, histopathological examination revealed that there was neither metastatic lymph nodes nor lymphoma cells in his right neck. Moreover, there was no lymphatic structure in his remnant lymph nodes.
This was a rare case in which complete remission of HL was confirmed by histopathological analysis. The absence of lymph node structure and lymphatic flow led to contralateral neck lymph node metastases of tongue cancer.

Renal cell carcinoma (RCC) is a malignant tumor that can metastasize easily. Hence, many patients have already developed metastasis when they are diagnosed. It is also one of the most common tumors that metastasize to the head and neck through extranodal disease. Herein, we reported a case of a 53-year-old man with cervical metastasis from bilateral RCC. Interestingly, whole exome sequencing (WES) and clonal evolution analysis revealed that bilateral renal tumor lesions and neck metastases (squamous cell carcinoma) share the same subclones and a large number of gene variants, while the pathological morphology is different (left nephrotic foci, a mixed pattern of mucinous tubular and spindle cell carcinoma (MTSCC) with papillary adenoma; right renal foci, papillary renal cell carcinoma (PRCC)). This was first reported in RCCs to the best of our knowledge. This case suggests that genotype analysis can be a powerful supplementary examination for clinical histopathological diagnosis. Gene detection has great significance for the accurate diagnosis and treatment of RCC metastasis or multiple lesions.

BACKGROUND: Post-pubertal teratomas, which mostly occur at 20 to 40 years old, are more likely to be found at a metastatic site in up to 20% of cases and may be inadvertently overlooked. We present a case of cervical malignant teratoma that masqueraded as a hematoma.Case presentation: A 24-year-old man presented to our institution with a 4-month history of a progressively relapsing painless mass in the neck, despite conservative treatments with oral medications. A huge space-occupying mass was identified with almost total occlusion of the left internal jugular vein. The likely diagnosis was an organized hematoma or congenital cystic tumor with internal hemorrhage. Surgical excisional biopsy of the mass lesion was conducted and a malignant teratoma was found. A whole-body positron emission tomography scan showed a left inguinal mass, bilateral intra-abdominal lymphadenopathies, and abdominal metastases. Histopathology further suggested the diagnosis of an immature testicular teratoma with multiple lymph node metastases. The patient received adjuvant chemotherapy with a bleomycin, etoposide, and cisplatin regimen. During follow-up, salvage second-line chemotherapy was required with a paclitaxel, ifosfamide, and cisplatin regimen.
CONCLUSIONS: Although uncommon, cervical teratoma should be taken into consideration once a painless and non-remitting mass lesion is found in a young adult.

Malignant conversion of sinonasal inverted papilloma (SNIP) occurs in approximately ten percent of cases. These tumors are classically described as locally destructive, but without metastatic potential. Only four cases of malignant conversion with cervical nodal metastases have been described in the English literature. We present the rare case of a 61-year-old Caucasian male with a nasopharyngeal recurrence of malignant SNIP with cervical and retropharyngeal nodal metastases. The patient underwent endoscopic transpterygoid with nasoseptal flap reconstruction, followed by staged bilateral and retropharyngeal node dissection. Histopathology of the specimens demonstrated poorly differentiated invasive nonkeratinizing squamous cell carcinoma with inverted-type features. Three months after surgery, the patient suffered from C1-C2 fractures consistent with osteoradionecrosis and expired. Although the rate of malignant conversion of SNIP is low, this case highlights the need for aggressive, definitive treatment and surveillance.