Clinicopathological characteristics and treatment outcomes of advanced SMARCA4-deficient thoracic tumors

PURPOSE

SMARCA4-deficient thoracic tumors, characterized by distinct clinicopathological, morphological, immunohistochemical, and genetic features, differ significantly from conventional non-small-cell lung carcinomas (NSCLCs). This group encompasses both SMARCA4-deficient NSCLCs (SMARCA4-NSCLCs) and SMARCA4-deficient undifferentiated tumors (SMARCA4-UTs). The efficacy of PD-1 inhibitors in treating SMARCA4-deficient thoracic tumors remains uncertain.

METHODS

Medical records of 36 patients diagnosed with stage IIIB, IIIC, or IV SMARCA4-deficient thoracic tumors were analyzed. We assessed the clinical, pathological, and genetic features of these patients through immunohistochemistry (IHC) and a 68-gene panel next-generation sequencing (NGS). We compared the differences between SMARCA4-NSCLCs and SMARCA4-UTs, and evaluated the impact of chemotherapy and immunotherapy on patient outcomes.

RESULTS

The majority of patients with SMARCA4-deficient thoracic tumors were heavy-smoking males, averaging 64.6 years in age. IHC predominantly showed weak or negative staining for markers such as TTF-1, CK5/6, p40, synaptophysin, chromogranin A, and CD56, which are often associated with adenocarcinoma, squamous cell carcinoma, and neuroendocrine tumors. The most common genetic mutations identified via NGS included TP53, CDKN2A, KRAS, STK11, NF1, and PTEN. No significant overall survival (OS) difference was observed between SMARCA4-NSCLCs and SMARCA4-UTs (p = 0.366). The median OS for patients treated with chemotherapy (n = 9) was 447 days, while the median OS for patients undergoing PD-1-inhibitor-based therapy (n = 16) was not reached (p = 0.105).

CONCLUSION

SMARCA4-deficient thoracic tumors exhibit distinct characteristics from conventional NSCLCs, and PD-1 inhibitors show promise in treating advanced SMARCA4-deficient thoracic tumors.

Thoracic SMARCA4-deficient undifferentiated tumor with associated granulomatous reaction and response to pembrolizumab

Thoracic SMARCA4-deficient undifferentiated tumor (SMARCA4-UT) is a rare entity that was recently described in the current World Health Organization Classification of Tumors. These lesions are highly aggressive with dismal prognosis, and most patients present with metastasis at the time of diagnosis. While there are about 100 cases of SMARCA4-UT described in the literature, there are only few existing reports that describe the cytomorphology of these lesions. We present a patient with masses involving the mediastinum, right lung, right supraclavicular lymph node and right adrenal gland. Subsequent core-needle biopsy of the right supraclavicular lymph node showed epithelioid to pleomorphic tumor cells with prominent nucleoli and associated granulomatous inflammation. The tumor cells were positive for CD34 and synaptophysin, and were negative for cytokeratins. SMARCA4 and SMARCA2 both showed loss of expression, which led to the diagnosis of SMARCA4-UT. The patient underwent treatment with pembrolizumab (PD-1 blocker), carboplatin, etoposide, and radiotherapy, resulting in an almost 55% reduction in the size of the primary tumor. Our case illustrates that an associated granulomatous inflammation might be an uncommon presentation of an already rare malignancy, and awareness of this phenomenon would prevent from mistaking SMARCA4-UT for other more well-known entities that can present with granulomas.

SMARCA4-deficient Undifferentiated Uterine Sarcoma: Clinicopathological Features of an Emerging Entity

SMARCA4-deficient undifferentiated uterine sarcoma is a recently described molecularly defined entity among the subset of aggressive undifferentiated uterine tumors. Mutation in the SMARCA4 gene is a key driver alteration, as also seen in small cell carcinoma of ovary, hypercalcemic type (SCCOHT) and thoracic undifferentiated carcinoma. Limited number of cases of SMARCA4-deficient undifferentiated uterine sarcoma has been reported in literature. We hereby describe a case of this distinct entity in a 52-year-old woman. Histomorphological examination showed sheets of monomorphic epithelioid cells with a variable proportion of cells displaying rhabdoid features, brisk mitotic activity, and lymphovascular invasion. A panel of immunohistochemical markers was required to exclude the differential diagnoses. The tumor was microsatellite stable. Loss of SMARCA4 expression and intact expression of INI1 in tumor cells by immunohistochemistry (IHC) confirmed the diagnosis of SMARCA4- deficient undifferentiated uterine sarcoma. The patient had a rapidly progressive clinical course.

Pleomorphic Sarcoma of the Oral Cavity: A Rare Case Entity

Pleomorphic sarcomas are extremely rare in the oral cavity, representing only 5% of all soft tissue sarcomas in the extremities of adults. They form a group of highly undifferentiated pleomorphic malignant tumors. A 36-year-old male reported to the OP with a chief complaint of a tooth ache in the right lower quadrant for the past 6 months. The patient gave a history of extraction of a mobile tooth in that region. A radiograph of the region was advised. An incisional biopsy was also done and sent for histopathological examination. The microscopy revealed the presence of spindle-shaped cells showing dysplastic features. A panel of immunohistochemical markers were performed to identify the tissue of origin of the lesion. The article details the clinical, radiographic, and microscopic features of a pleomorphic soft tissue lesion along with the array of immunohistochemical markers, leading to the final diagnosis of such enigmatic lesions.

Metastasis in the mandible involving gingiva: An intriguing case with a perplexing pathology

Oral metastasis, although rare, tends to involve jawbones, particularly the posterior region of the mandible, and involvement of oral soft tissues, even when less likely, is most often seen on the gingiva and tongue. Clinically, the soft-tissue masses tend to mimic pyogenic granuloma, peripheral giant cell granuloma or an epulis and thus are difficult to diagnose and identify. The jaw bone is preferred by prostate carcinoma as a metastatic target. Prostate malignancy, which is more common in Western countries than in India, may be adenocarcinomas or carcinomas. Oftentimes, metastatic lesions develop in the alveolar region and are a cause for tooth mobility, yet, they tend to be detected only after extraction of the affected tooth. In such cases, the symptomatic presentation therefore, is vague and indicative of tooth mobility secondary to periodontal pathology unless, a detailed history and follow-up is done. We report a case of a male patient who presented to our department with a proliferative, painful, swelling postextraction of the left first molar region, and the lesion was seen at the extraction site as well as in the mandibular anterior tooth region. The swelling was associated with palpable lymph nodes. Orthopantomogram showed an irregular, radiolucent lesion extending from the lower left central incisor to the left first molar region in the mandibular alveolus. Incisional biopsy tissue came with provisional diagnosis of osteomyelitis or squamous cell carcinoma as the patient was a habitual bidi smoker for more than 20 years. Histologically, it was an undifferentiated tumor with tumor cells seen in deep connective tissue with a lack of lineage differentiation. An undifferentiated malignant tumor represents either a metastasis of unknown origin or a primary neoplasia without obvious cell line of differentiation. Immunohistochemistry (IHC) of undifferentiated tumors helps to categorize them into small round blue cell tumors or large cell tumors. The oral pathologist was perplexed as there was no mention of any other malignancy in the patient's history, which, however, was noted by the surgeons few days later. Hence, initially, a hematopoietic malignancy was suspected which was ruled out by IHC, and later, staining with cytokeratin 7 (CK7), CK-high molecular weight and P63 confirmed prostate metastases as all three were negative.

Undifferentiated metastatic renal cell carcinoma presenting as a cutaneous nodular lesion

Cutaneous metastases may be the first sign of clinically silent visceral cancer. Approximately 30% of patients with primary renal cell carcinoma present with metastatic disease, and only 8% of them have skin metastases. We present the case of a 59-year-old male patient with a subcutaneous nodular on the upper chest extending to the jugular region. The lesion appeared skin colored and was not painful and 5 cm × 3.5 cm in diameter. The histological examination of the cutaneous biopsy showed an infiltration of undifferentiated epithelial cells positive to cytokeratins AE1/AE3, whereas they were negative to CK-20, CK5/6, cluster of differentiation 10, vimentin, thyroid transcription factor-1, S-100, human melanoma black-45, hepatocyte-specific antigen, carcinoembryonic antigen, and chromogranin A. A total-body computed tomography (CT) showed the presence of a tumoral lesion in the left kidney with multiple metastases in the lung, brain, and bones. According to the cutaneous biopsy and total-body CT, a final diagnosis of an undifferentiated renal carcinoma presenting as a subcutaneous metastasis was made. A chemotherapeutic treatment with gemcitabine and cisplatin resulted in the stabilization of the renal and metastatic lesions with an improvement in the quality of life of the patient. Considering that the prognosis of patients with cutaneous metastases is very poor, it is necessary to obtain an appropriate diagnosis in order to identify patients with treatable disease with the purpose of starting a therapeutic protocol.