Micropapillary pattern in a case of multilocular cystic renal neoplasm of low malignant potential

Archana S Bhat; Muktha R Pai; Nisha J Marla; Manjunath Shetty; Joyce Jesudas

doi:10.4103/jina.jina_37_16

CASE REPORT

Year : 2017 | Volume : 4 | Issue : 3 | Page : 101-103

Micropapillary pattern in a case of multilocular cystic renal neoplasm of low malignant potential

Archana S Bhat¹, Muktha R Pai², Nisha J Marla¹, Manjunath Shetty³, Joyce Jesudas⁴
¹ Department of Pathology, Father Muller Medical College, Mangalore, Karnataka, India
² Department of Pathology, A J Institute of Medical Sciences, Mangalore, Karnataka, India
³ Department of Urology, Father Muller Medical College, Mangalore, Karnataka, India
⁴ Department of Surgery, Father Muller Medical College Hospital, Mangalore, Karnataka, India

Date of Web Publication

28-Sep-2017

Correspondence Address:
Archana S Bhat
Department of Pathology, Father Muller Medical College, Mangalore, Karnataka
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jina.jina_37_16

Abstract

Multilocular cystic renal neoplasm of low malignant potential, formerly known as multilocular cystic renal cell carcinoma, is a relatively uncommon renal neoplasm. The peculiarity of this neoplasm lies in the absence of expansile solid nodules. We report a case of this uncommon neoplasm with a focal micropapillary pattern, which is a very rare feature. To the best of our knowledge, there are no case reports emphasizing on the micropapillary pattern in case of multilocular cystic renal neoplasm of low malignant potential. We report a case of a 57-year-old female patient who presented with pain abdomen. Ultrasound and computerized tomography of abdomen revealed a multilocular cystic renal mass. The patient underwent right nephrectomy and the specimen was sent for histopathological examination. Grossly, the enlarged lower pole on cutting open showed multiloculated fluid-filled cyst with smooth inner walls. Microscopically, the tumor was composed of cysts lined by cells with clear cytoplasm and of Fuhrman nuclear Grade 1. A rare feature seen was the disposition of tumor cells in micropapillary pattern. The case was reported as multilocular cystic renal neoplasm of low malignant potential. This neoplasm needs special consideration due to its good prognosis and potential amenability to cure by nephron-sparing surgery. Also to be noted is that a multilocular cystic renal neoplasm of low malignant potential can have a micropapillary pattern too.

Keywords: Micropapillae, multicystic renal cell carcinoma, multilocular cystic renal cell carcinoma, multilocular cystic renal neoplasm of low malignant potential

How to cite this article:
Bhat AS, Pai MR, Marla NJ, Shetty M, Jesudas J. Micropapillary pattern in a case of multilocular cystic renal neoplasm of low malignant potential. J Integr Nephrol Androl 2017;4:101-3

How to cite this URL:
Bhat AS, Pai MR, Marla NJ, Shetty M, Jesudas J. Micropapillary pattern in a case of multilocular cystic renal neoplasm of low malignant potential. J Integr Nephrol Androl [serial online] 2017 [cited 2023 Oct 1];4:101-3. Available from: http://www.journal-ina.com/text.asp?2017/4/3/101/215742

Introduction

Multilocular cystic renal neoplasm of low malignant potential is a relatively rare renal neoplasm with a very good prognosis.^[1] The WHO 2015 classification of renal neoplasms has renamed multilocular cystic renal cell carcinoma (MLRCC) as multilocular cystic renal neoplasm of low malignant potential.^[2] The peculiarity of this neoplasm lies in the absence of expansile solid nodules. Multilocular cystic renal neoplasm of low malignant potential constitutes <1% of all renal tumors.^[2] It has a male predominance with mean age at presentation being 50 years.^[3] This entity needs to be differentiated from conventional renal cell carcinoma (RCC) because of its good prognosis. We report a case of MLCRCC with micropapillae which is a very rare feature. To the best of our knowledge, there are no case reports emphasizing on the micropapillary pattern in case of multilocular cystic renal neoplasm of low malignant potential.

Case Report

We report a case of a 57-year-old female patient who presented with pain abdomen. Ultrasound and computerized tomography of abdomen revealed a unifocal mass in the lower pole of the right kidney [Figure 1]. The mass was entirely composed of multiloculated cysts separated by thin septa. There were no solid-intervening areas. The patient underwent right radical nephrectomy and the specimen was sent for histopathological examination. On gross examination, the lower pole appeared enlarged. On cutting open, multiloculated fluid-filled cysts with smooth inner walls were noted [Figure 2]. Microscopic examination showed tumor entirely composed of cysts lined by cells with clear cytoplasm and Fuhrman nuclear Grade 1. A rare feature seen was the disposition of tumor cells in micropapillary pattern [Figure 3].

Figure 1: Computed tomography scan showing multilocular cystic mass with thin septa occupying lower pole of the right kidney

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Figure 2: Cut surface of the kidney showing multicystic mass with no intervening solid areas

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Figure 3: Cyst lined by clear cells with intracystic micropapillae, (H and E stain, ×400)

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Discussion

Multilocular cystic renal neoplasm of low malignant potential is a rare renal neoplasm with a very good prognosis. The WHO 2015 defines this as a tumor entirely composed of numerous cysts, the septa of which contains individual or groups of clear cells without expansile growth.^[2] Majority of the cases are clinically asymptomatic and diagnosed incidentally. These tumors are more common in males with mean age at presentation being around 50 years.^[3]

These tumors need to be differentiated from clear cell RCC with cystic change, cystic nephroma, clear cell papillary RCC with cystic change, tubulocystic RCC, and benign renal cysts. In clear cell RCC with cystic change, solid areas composed of sheets of clear cells are noted along with areas of hemorrhage and necrosis.^[2] Cystic nephroma has the peculiar ovarian-like stroma and hob-nailing of the nuclei which are not seen in multilocular cystic renal neoplasm of low malignant potential.^[2] Clear cell papillary RCC has predominant papillary architecture unlike multilocular cystic renal neoplasm of low malignant potential.^[4] In tubulocystic RCC, the cysts are lined by flat cuboidal cells with eosinophilic cytoplasm and variable nuclear atypia, usually of higher Fuhrman nuclear grades unlike multilocular cystic renal neoplasm of low malignant potential.^[5]

The good prognosis associated with multilocular cystic renal neoplasm of low malignant potential can be explained by the presence of fewer number of tumor cells, low mitotic rate, and low Fuhrman nuclear grade.^[6]

Various studies have been done to decipher the association between conventional RCC and multilocular cystic renal neoplasm of low malignant potential. Chromosome 3p deletions have been found in 74% cases of multilocular cystic renal neoplasm of low malignant potential, and VHL mutations have been found in 25% cases of multilocular cystic renal neoplasm of low malignant potential. In most of the cases, the multilocular cystic renal neoplasm of low malignant potential tumor cells expresses strong positivity for PAX 2 and CA-9.^[7],[8]

There have been few follow-up studies on patients treated surgically for multilocular cystic renal neoplasm of low malignant potential, confirming the excellent prognosis and outcome. As such, 65% of the participants at the RCC Consensus Conference held at Vancouver suggested the redesignation of MLCRCC as “multilocular cystic renal neoplasms of low malignant potential.”^[6],[9] Furthermore, the majority of the participants (78%) by consensus believed that Fuhrman nuclear Grade 2 is also acceptable in multilocular cystic renal neoplasm of low malignant potential.^[9] Our case also has micropapillary pattern which is a very rare feature.^[9]

Conclusion

MLCRCC is entirely cystic but occasionally micropapillae can also be seen. This neoplasm needs special consideration due to its good prognosis and potential amenability to cure by nephron-sparing surgery.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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