Table of Contents
Definition / general | Essential features | Terminology | Epidemiology | Clinical features | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Positive stains | Negative stains | Electron microscopy description | Molecular / cytogenetics description | Molecular / cytogenetics images | Differential diagnosis | Additional references | Board review style question #1 | Board review style answer #1Cite this page: Andeen NK, Tretiakova M. Mucinous tubular and spindle cell carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/kidneytumormalignantmucinoustubular.html. Accessed March 24th, 2023.
Definition / general
- Renal epithelial neoplasm characterized by "tubular formations merging with bland spindle cells and a myxoid stroma" (WHO 2016)
- Low grade polymorphic renal epithelial neoplasm with variable components of tubular architecture, extracellular basophilic mucinous material and spindle cell areas
- First described in 2001 - 2002 (Hum Pathol 2001;32:506, Mod Pathol 2002;15:1162); prior cases classified as sarcomatoid papillary renal cell carcinoma or unclassified
Essential features
- Usually bland renal epithelial neoplasm with tubules merging with bland spindle cells in a myxoid stroma; behavior generally indolent
- May share immunohistochemical (CK7+, AMACR+) and morphologic features with papillary renal cell carcinoma but genetically distinct
Terminology
- Previously called low grade tubular mucinous renal neoplasm, low grade collecting duct carcinoma, low grade myxoid renal epithelial neoplasm with distal nephron differentiation
Epidemiology
- Accounts for < 1% of all renal neoplasms
- Median age 58 years (range 13 - 81)
- F:M = 4:1 (Diagn Pathol 2015;10:168)
Clinical features
- Usually indolent behavior
- Recurrences are uncommon
- Metastases are rare but have been reported with both low grade histology and high grade transformation (Histol Histopathol 2008;23:1517, Int J Clin Exp Pathol 2008;1:180, Moch: WHO Classification of Tumours of the Urinary System and Male Genital Organs (IARC WHO Classification of Tumours), Fourth Edition, 2016)
- Some occur in association with nephrolithiasis
Case reports
- A woman in her 50s underwent nephrectomy for an incidentally identified 5.1 cm renal mass (Case of the Month #501)
- 66 year old woman (Can Urol Assoc J 2008;2:635)
- Cases with sarcomatoid change (Am J Surg Pathol 2009;33:44, Hum Pathol 2008;39:966)
- Unclassified tumor resembling pleomorphic adenoma (Am J Surg Pathol 2007;31:632)
- Metastasis to liver and lymph node without sarcomatoid change (Hum Pathol 2011;42:444)
Treatment
- Resection; additional therapy may be indicated
Gross description
- Well circumscribed, 2 - 10 cm (mean 4 cm)
- Confined to kidney; grayish white to tan to yellow glistening cut surface; may have focal hemorrhage; no renal vein invasion
Microscopic (histologic) description
- Long tubular profiles or cord-like growth pattern of uniform, bland, low cuboidal cells with eosinophilic, focally vacuolated cytoplasm which transition to anastomosing spindle cells
- Stroma is myxoid and bubbly with abundant extracellular mucin; focal clusters of foamy macrophages
- Well circumscribed with partial surrounding rim of compressed fibrous tissue
- Some cases may be mucin poor (highlighted by Alcian blue)
- May have well formed papillae, clear cells, foamy macrophages, necrosis (Am J Surg Pathol 2006;30:1554, Ann Diagn Pathol 2007;11:13) or rarely neuroendocrine differentiation (Am J Clin Pathol 2006;125:99)
- Rare high grade nuclei and sarcomatoid change have been described
- Generally no desmoplasia, no inflammation, no infiltrative growth, no hobnail epithelium, no cysts
Microscopic (histologic) images
Contributed by Nicole K. Andeen, M.D. and Maria Tretiakova, M.D., Ph.D.
Contributed by Dr. Constantina Petraki and the Genitourinary Pathology Society (Case #501)
Images hosted on other servers:
Cytology description
- Epithelial tumor with round to oval nuclei associated with strands of metachromatic stromal tissue (Diagn Cytopathol 2007;35:593)
- Report of 2 cases by FNA (Diagn Cytopathol 2010;38:51)
Positive stains
- PAX2, PAX8
- EMA (95%), AMACR (93%, Am J Surg Pathol 2006;30:13, Hum Pathol 2006;37:698)
- AE1 / AE3, low molecular weight keratins: CK7 (81%), CK 8 / 18, CK19
- PAS (highlights basal lamina around tubules), Alcian blue highlights mucin; E-cadherin (Diagn Pathol 2015;10:168)
- Also neuron specific enolase and either chromogranin or synaptophysin (Histol Histopathol 2006;21:7)
- Occasionally high molecular weight cytokeratin 34 beta E12 (15%), vimentin, Ulex or CD10 (15%)
Electron microscopy description
- Moderate amount of mitochontria, rough endoplasmic reticulum, dense core granules and focal microvilli
- No renin granules or glycogen (Pathol Int 2004;54:201)
Molecular / cytogenetics description
- Hypodiploid with multiple chromosomal losses (-1, -4, -6, -8, -9, -13, -14, -15, -22), some hypertriploid but no identifiable pattern (Mod Pathol 2006;19:186)
- No trisomies 7 / 17 or loss of Chr Y
Differential diagnosis
- Collecting duct carcinoma: high nuclear grade, desmoplasia and infiltrative features; mucinous tubular and spindle cell carcinoma is usually low grade and well circumscribed
- Metanephric adenoma: lacks spindled cells and mucinous stroma; positive for WT1 and CD57, negative for AMACR and CK7
- Papillary renal cell carcinoma (PRCC): both papillary renal cell carcinoma and mucinous tubular and spindle cell carcinoma may have papillae, mucin, low grade features, foam cells, AMACR and CK7 expression
- look for more prominent mucinous tubular and spindle cell carcinoma biphasic features of anastomosing tubules with spindle cells in mucinous stroma
- PRCC diffusely express CD10 and has classic trisomy 7 / 17 genomic signature (Am J Surg Pathol 2008;32:1353, Mod Pathol 2006;19:488)
- Sarcomatoid renal cell carcinoma: infiltrative, usually a high degree of nuclear pleomorphism, areas of more typical renal cell carcinoma subtypes
- Smooth muscle tumor: more distinct fascicular architecture, absence of tubular areas
Additional references
Board review style question #1
If necessary, one reliable feature to distinguish mucinous tubular and spindle cell carcinoma from papillary renal cell carcinoma in a challenging case is:
- Clinical and radiographic evaluation
- Genomic evaluation
- Immunohistochemistry
- Morphologic features of papillary growth and foam cells
Board review style answer #1
B. The papillary genomic signature of +7, +17 and loss of chromosome Y is not shared with mucinous tubular and spindle cell carcinoma
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Reference: Mucinous tubular and spindle cell carcinoma
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Reference: Mucinous tubular and spindle cell carcinoma