A Rare Case of Squamous Cell Carcinoma of the Renal Parenchyma With Sarcomatoid Differentiation

INTRODUCTION

Squamous cell carcinoma (SCC) of the renal pelvis accounts for 0.5–0.8% of malignant renal tumours.^[1–10] SCC of the renal parenchyma with sarcomatoid differentiation is even rarer, with only a few reported cases in the literature.^[11] Contributing factors for renal SCC are nephrolithiasis, urinary tract infections (UTIs), endogenous and exogenous chemicals, hormonal imbalance, and vitamin A deficiency.^[12] Due to its rarity, diagnosis of SCC of renal parenchyma can be challenging. This report highlights a case where SCC of renal parenchyma with sarcomatoid differentiation was diagnosed in a patient who underwent surgical treatment for renal calculi with recurrent UTI.

CASE REPORT

A 56-year-old male patient with ischaemic heart disease and hypertension who is a non-smoker and non-alcoholic presented with fever with chills, left flank pain, and haematuria for two months. He had a history of left complex staghorn calculi treated by left retrograde intrarenal surgery (RIRS) and left percutaneous nephrolithotomy (PCNL) one month ago at another hospital, followed by recurrent UTI. Subsequently, the patient had features of sepsis and was referred for further evaluation and treatment of residual calculi. The urine culture was negative. Blood culture was positive for Staphylococcus epidermidis, and culture-sensitive antibiotics were prescribed. Haematological investigations revealed a white cell count (WCC) of 24,530 cells/cumm (4000–10000), which raised to 79,820 cells/cumm, haemoglobin (Hb) of 9.5 g/dL (11.6–16.4 g/dL), ESR- 89 (0–14 mm/hr), serum calcium 9.3 (8.4–10.2 mg/dL), and serum creatinine 0.8mg/dL (0.5–1.5mg/dL). Ultrasound (USG) abdomen, done at the time of admission, was suggestive of multiple left renal calculi, dilated upper and middle pelvicalyceal system of the left kidney with echogenic debris within. These findings indicated pyonephrosis.

The patient underwent urgent intervention by percutaneous nephrostomy drainage on the second day of admission to buy time because the patient had severe sepsis. Once his general condition improved, he was evaluated with contrast enhanced computerised tomography (CECT) abdomen and pelvis with CT urography [Figure 1], which showed a heterogenous mass in the upper pole/interpole region of left kidney which measured approximately 5.3 × 4.8 × 7 cm, left adrenal lesion which measured approximately 3.1 × 2.7 × 2.8 cm, enlarged conglomerated left para-aortic lymph node. This was suggestive of a left renal cell carcinoma (RCC), probably stage IV T4N1M0.

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Figure 1:

CECT abdomen and pelvis with CT Urography showing a large heterogeneous mass in the posterior cortex of the interpole and upper pole region of the left kidney, calcification/calculi seen embedded within (blue arrow). CECT: Contrast-enhanced computed tomography, CT: Computerised tomography.

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He underwent a USG-guided left renal mass biopsy 3 weeks after percutaneous nephrostomy, which showed features of a poorly differentiated carcinoma. The IHC panel was positive for PanCK, EMA, CD10, p63, CAIX, CK7, and INI-1 retained. The overall features were in favour of a diagnosis of renal SCC with focal sarcomatoid differentiation [Figures 2 and 3].

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Figure 2:

Immunohistochemistry for EMA tumour cells. (EMA, 40x)EMA: Epithelial membrane antigen.

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Figure 3:

Immunohistochemistry for Pan CK tumour cells. (Pan CK, 40x). Pan CK: Pan-cytokeratin.

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Contrast enhanced 18F-FDG (fluorodeoxyglucose) whole body PET-CT (Positron Emission Tomography-Computed Tomography) scan showed increased FDG uptake in left adrenal nodule, large hypodense lesion involving the upper pole, interpolar region and lower pole of left kidney, hypermetabolic left retrocrural deposit noted eroding the adjacent D12 vertebra, in left retrocrural deposit, eroding the adjacent D12 vertebra, in the large hypodense/necrotic lesion in left para-aortic region, close to the left kidney anterior to the psoas muscle [Figure 4].

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Figure 4:

Contrast-enhanced 18F-FDG Whole Body PET-CT scan showing increased FDG uptake in the left adrenal nodule, large hypodense lesion involving the upper pole, interpolar region, and lower pole of left kidney (blue arrow). (a): Axial CT section; (b): Corresponding MIP (maximum intensity projections) PET image; (c): Corresponding axial fused PET CT image showing FDG avid areas; (d) Sagittal whole body MIP image. FDG: Fluorodeoxyglucose; PET-CT: Positron emission tomography.

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A multidisciplinary tumour board meeting including a urologist, a medical oncologist, and a radiation oncologist decided to go ahead with a left open radical nephrectomy, followed by chemoradiotherapy. Three units of blood transfusion were done. The patient underwent left open radical nephrectomy, but lymph nodes could not be removed completely because of severe perinephric adhesions (especially the hilum) and involvement of major vessels. Postoperatively, the patient developed severe leucocytosis, hypotension, which was managed in the ICU (intensive care unit) with ionotropes, IV fluids, and two units of blood transfusion. The patient's general condition improved, and he was discharged.

The histopathology report showed renal SCC, with the tumour extending into the left adrenal gland, perinephric fat, Gerota's fascia, renal sinus, and the pelvicalyceal system. The tumour cells were highly pleomorphic, with round to oval nuclei, moderate eosinophilic cytoplasm [Figure 5], extensive areas of squamoid differentiation, keratin pearls tumour giant cells, and bizarre cells [Figure 6]. Focal sarcomatoid differentiation was noted [Figure 7].

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Figure 5:

Tumour cells are highly pleomorphic with round to oval nuclei, and moderate eosinophilic cytoplasm (blue arrow). Haematoxylin and eosin, 40x.

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Figure 6:

Extensive areas of squamoid differentiation, keratin pearls noted (blue arrow). Haematoxylin and eosin, 40x.

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Figure 7:

Focal sarcomatoid differentiation noted (blue arrow). Haematoxylin and eosin, 40x.

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One month post-operatively, the patient received 20 Grays/5fractions/1week radiation therapy followed by chemotherapy, 4 cycles of Inj. Paclitaxel 100mg + Inj. carboplatin 150mg. However, due to high stage and sarcomatoid differentiation, the response to radiation and chemotherapy was poor, and he developed extensive metastasis to lungs, liver, and vertebrae. He succumbed to the disease after receiving four cycles of chemotherapy.

DISCUSSION

SCC of renal parenchyma with sarcomatoid differentiation is exceptionally rare, with only a few reported cases in the literature.^[11]

Sarcomatoid dedifferentiation is often seen in clear cell RCC (5% of ccRCC cases) and chromophobe RCC (8% of ChRCC cases). They are associated with poor prognosis and complicate the diagnosis and treatment. Our case illustrates the aggressive nature of SCC with squamous differentiation, which often presents at advanced stages with limited treatment options.^[13]

The minimum percentage of sarcomatoid dedifferentiation to establish the diagnosis of (sarcomatoid renal cell carcinoma) sRCC is not required.^[13] Sarcomatoid dedifferentiation is associated with a poor prognosis and is more frequently observed in stage III and IV disease.^[14] A study done in the Mayo Clinic showed that the risk of death increased by 6% for every 10% increase in sarcomatoid dedifferentiation.^[15]

In our case patient underwent multiple procedures for urolithiasis but continued to have urinary tract infection (UTI). Patient history, clinical examination, ultrasonography KUB (ultrasound of kidneys, ureters, and bladder), and CECT-scan done at outside hospital did not show any sign of a tumour in the patient. A definitive diagnosis of renal SCC with sarcomatoid differentiation was made after further evaluating the patient with CECT KUB, renal biopsy, IHC, and post-operative histopathology report. Important histological findings of SCC are keratin pearls formation and intercellular bridge and sarcomatoid differentiation. Pre-operative biopsy IHC showed pan-cytokeratins and/or epithelia membrane antigen, which are often focally expressed in the sarcomatoid component of RCCs but are negative in sarcomas.

Patients with renal SCC present at an advanced stage, usually at least T3 or higher, and have poor prognosis.^[9] and only a few reported cases of sarcomatoid differentiation in SCC of the renal parenchyma.^[11]

The patient in the current case report had stage IV disease at the time of diagnosis. Because of the rarity of the disease, there is still no standardized protocol for the management of patients with primary renal SCC with sarcomatoid differentiation. Our patient underwent radical nephrectomy with adjuvant chemoradiotherapy. However, the patient succumbed to the disease because of its advanced stage and poor prognosis associated with sarcomatoid differentiation. Further studies are required in literature to determine whether chemotherapy or radiotherapy can improve patient outcomes.

CONCLUSION

Renal parenchyma SCC with sarcomatoid differentiation is a rare and aggressive tumour with a poor prognosis, often diagnosed at advanced stages. Due to the lack of established treatment guidelines, management typically involves radical nephrectomy with chemoradiotherapy. Further studies are necessary to develop effective treatment strategies and improve patient outcomes.