Base of tongue metastasis of cutaneous malignant melanoma with rhabdoid and neuroendocrine features: Report of a rare case and review of the literature

Metastatic malignant melanoma (MM) represents a highly aggressive cancer associated with overall poor prognosis. Various anatomic sites can be affected, including the oral cavity and the oropharynx. It may mimic other entities by assuming a variety of clinical appearances and exhibiting a plethora of microscopic variations. Herein, we present a case of a 63-year-old male with a MM metastasizing to the base of tongue, which developed 5 years after the original diagnosis and treatment of cutaneous MM of the chest and heralded its relapse; subsequently, neurological symptoms developed as a result of metastasis to the brain. Diagnostic challenges were encountered, as the tongue lesion clinically masqueraded as a pedunculated reactive lesion and microscopically displayed unusual rhabdoid and neuroendocrine features. Tumor cells expressed S-100, HMB-45, Melan-A, and SOX-10, while most cells with rhabdoid morphology were also positive for myogenin and Myo-D1. Chromogranin and synaptophysin positivity was further noticed in a subset of cells, suggestive of focal neuroendocrine differentiation. Molecular investigation revealed mutations for the BRAF V600E gene. Divergent differentiation of tumor cells may cause diagnostic pitfalls necessitating thorough immunohistochemical analysis. The presence of rhabdoid features and neuroendocrine differentiation are very uncommon, while their co-existence is extremely rare. Better characterization of such microscopic variations in MMs with evaluation of their potential biologic significance is warranted.

Metastatic renal cell carcinoma involving colon with unusual histologic features and diagnostic challenges: A case report

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Metastatic RCC in the colon, although very rare, should be kept in the differential diagnosis of patients with lower GI bleeding, particularly patients with a prior history of kidney mass or nephrectomy

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Most common type of primary or metastatic RCC is Clear-cell-type.

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We reported the first case of rhabdoid-RCC metastasizing to colon.

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In the absence of IHC-stains, rhabdoid-RCC may be misdiagnosed as soft-tissue-sarcoma or other poorly differentiated carcinomas.

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Our case exclusively occurred in a woman while colonic metastasis of RCC commonly occurring in males.

Introduction and importance

Renal cell carcinoma (RCC) accounts for 3% of all malignancies in adults, on its own being the 3rd most common urologic malignancy. Commonly RCC metastasizes to lung, bone, liver, brain but rarely to colorectum. Here we present the metastasis of RCC to colon with unusual histologic features.

Case presentation

A 40-year-old woman presented with abdominal pain and constipation. Colonoscopy showed an ulcerative mass 30 cm from anal verge. Subsequently, she underwent abdominoperineal resection of the involved portion of colon and the biopsy was sent to us for histopathological analysis. Grossly, it was a large fungating mass. Microscopic examination revealed a malignant neoplasm with polygonal cells, abundant eosinophilic cytoplasm, eccentric nuclei and prominent nucleoli. Immunohistochemistry confirmed the diagnosis of RCC.

Clinical discussion

Colon rarely infiltrated by metastasis from RCC and so far, around 25 of such cases have been reported in the literature. Most common metastatic type of RCC to gastrointestinal tract is clear cell type. In our patient, the type of the metastatic RCC to colon was RCC with rhabdoid features. RCC with rhabdoid features is rare (3–5% of all RCC), but it is highly aggressive with higher chance of metastasis, extra renal invasion and poorer prognosis.

Conclusion

RCC should be considered as one of the differential diagnosis of colorectal cancers. Appropriate immunohistochemical workup would then reveal the correct diagnosis.

Clinicopathologic characteristics of prostatic stromal sarcoma with rhabdoid features: A case report

BACKGROUND

Prostatic stromal sarcoma presenting with rhabdoid features is extremely rare, and only four cases have been reported in the English-language literature to date. Accordingly, there is no absolute definition of this group of tumors as yet, and our overall understanding of its morphological features, therapeutic regimen and prognosis is limited.

CASE SUMMARY

A 34-year-old male patient was referred to our hospital to address a 2-mo history of hematuria and progressive dysuria. Pelvic computed tomography scan revealed a 6.0 cm × 5.2 cm × 7.2 cm mass in the prostate, with bladder invasion. The patient underwent transurethral prostatectomy as upfront therapy. He refused further treatment and died of uncontrollable tumor growth 3 mo after surgery. Pathology analysis revealed the stroma to be pleomorphic, with a huge number of atypical spindle cells. Rhabdomyoblastic cells, with abundant eosinophilic cytoplasm, were detected. The spindle cells were positive for vimentin, INI1 and β-catenin, and the rhabdomyoblastic cells were positive for MyoD1, myogenin and INI1. The spindle cells and epithelial cells were sporadically positive for P53.

CONCLUSION

The prostatic stromal sarcoma tumor was immunoreactive for β-catenin, suggesting a role for the Wnt/β-catenin pathway in this tumor type.

SMARCB1- and vimentin-positive esophageal carcinoma with undifferentiated components, rhabdoid features, and a good prognosis: a case report

BACKGROUND

Undifferentiated carcinoma of the esophagus with rhabdoid features is a very rare histologic finding that is occasionally associated with the loss of SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1 (SMARCB1); however, until now, few survey reports of this type of tumor have been published. In this study, we describe a case of esophageal carcinoma with undifferentiated components and rhabdoid features that was exclusively positive for vimentin and SMARCB1 in a patient with prolonged survival.

CASE PRESENTATION

A 67-year-old man complained of a stomachache and loss of appetite persisting for 1 month. He was then admitted to the hospital. Diagnostic imaging studies revealed a transdiaphragmatic circular ulcerative tumor of the esophagogastric region. Biopsy specimens showed undifferentiated round cell carcinoma. The patient underwent lower esophageal resection and total gastrectomy with lymph node dissection. Microscopic analysis revealed that most of the primary tumor consisted of large undifferentiated round cells and scattered rhabdoid cells. The tumor invaded the muscular layer in the esophagus and the subserosal layer in the stomach, and metastasis was noted in only one lymph node. Immunohistochemical analysis revealed that the round and rhabdoid cells found in the primary tumor were diffusely positive for SMARCB1 and vimentin. The tumor displayed focal positivity for the anti-pan-cytokeratin antibody AE1/AE3. In the positive lymph node, round undifferentiated carcinoma cells were admixed with squamous carcinoma cells that were positive for cytokeratin 5/6 and 34βE12. The MIB-1 index was 19.7% and 0.5% for the round cells from the primary tumor and epithelial cells from the metastatic lymph node lesion, respectively, and 70.1% for the round cells from the metastatic lymph node lesion. The patient has been alive for 10 years after surgery without tumor recurrence.

CONCLUSIONS

We reported a rare case of esophageal carcinoma with undifferentiated components, rhabdoid features, and a good prognosis.