Low-grade Tubular Myxoid Renal Tumors: A Clinicopathological Study of 3 Cases

Abstract

We report 3 cases of a new renal cell tumor entity with a review of the literature. These 3 cases were retrieved from the files of this institution from 1991 to 2002. The clinical data and all histologic slides were reviewed and an immunohistochemical study was performed. Patients were all females. Tumors were almost similar with well-defined margins. Tumor architecture was tubular and focally fusiform with an abundant myxoid stroma. Tumor cells were low cuboidal, slightly eosinophilic with low nuclear grade. Immunohistochemistry was in favor of a distal nephron differentiation. All patients were healthy after surgery. We describe 3 cases of a new clinicopathological entity entitled low-grade tubular myxoid renal tumor with a benign clinical course.

Immunohistochemical Analysis of Mucinous Tubular and Spindle Cell Carcinoma and Papillary Renal Cell Carcinoma of the Kidney

“…4,11,12,21,23,28,31 Papillary RCC, the second most common RCC subtype comprising 11% to 18%, has a proclivity for lymph node metastasis in 7% of cases and overall 5-year survival rate of approximately 86%. 2,3,6,8,18 Sarcomatoid or spindle cell dedifferentiation is reported in 3% to 5% of papillary RCC and is a strong indicator for adverse prognostic outcome with a 1-year and 5-year survival of 59% and 22%, respectively.…”

“…1 Among the newly recognized RCC subtypes is the uncommon mucinous tubular and spindle cell carcinoma, which in its classic histologic form shows an admixture of low-grade tubular cuboidal cells and arrays of spindle cells in a mucinous stroma. 4,11,12,21,23,[26][27][28]31 This tumor type appears to portend a favorable clinical outcome. 4,11,12,21,23,26,28,31 Because of the rarity and recent description of mucinous tubular and spindle cell carcinoma, some cases of this entity, sent to us in consultation, have been submitted with a question of papillary RCC with sarcomatoid change.…”

“…4,11,12,21,23,[26][27][28]31 This tumor type appears to portend a favorable clinical outcome. 4,11,12,21,23,26,28,31 Because of the rarity and recent description of mucinous tubular and spindle cell carcinoma, some cases of this entity, sent to us in consultation, have been submitted with a question of papillary RCC with sarcomatoid change. The tubular cells of mucinous tubular and spindle cell carcinoma resemble the basophilic type (type 1) papillary RCC cells, and the spindle cell arrays in mucinous tubular and spindle cell carcinoma may mimic the solid, trabecular, and compact papillary areas of papillary RCC.…”

Renal mucinous tubular and spindle carcinoma lacks the gains of chromosomes 7 and 17 and losses of chromosome Y that are prevalent in papillary renal cell carcinoma

“…1,2 Until its recognition as a distinct neoplastic entity by the World Health Organization (WHO) consensus conference, mucinous tubular and spindle cell carcinoma had been previously sporadically reported with a variety of names, usually pointing out the morphologic relationships with the distal nephron and the loop of Henle or highlighting the spindle cell component. [3][4][5][6][7][8][9][10][11] Since mucinous tubular and spindle cell carcinomas have generally been described as low-grade and low-stage malignancies, usually cured by surgery, 1,4,8,[12][13][14] differentiation from other primary malignancies of the kidney is important. The differential diagnosis has to take into consideration primarily papillary renal cell carcinoma, type 1, that may share with mucinous tubular and spindle cell carcinomas several pathologic features, such as tubular, trabecular or papillary architecture, lowgrade or moderate nuclear atypia, and the presence of foamy macrophages and inflammatory cells.…”

Myxoid Renal Tumor With Myoepithelial Differentiation Mimicking a Salivary Gland Pleomorphic Adenoma: Description of a Case

“…Even recently, further reports appeared in the literature to confirm the pathologic features and benign behavior of such tumor entity. 2,10,22 In the present report, we describe a single tumor of the kidney, arising in an adult man, which displayed some of the morphologic hallmarks typical of low-grade myxoid renal epithelial neoplasms, but showing additional peculiar and unique morphologic features and an immunohistochemical profile consistent with myoepithelial differentiation.…”