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Mucinous tubular and spindle cell carcinoma
Mucinous tubular and spindle cell carcinoma
Specialty	Oncology/nephrology

Mucinous tubular and spindle cell carcinoma (MTSCC) is a rare subtype of renal cell carcinoma (RCC), that is included in the 2004 WHO classification of RCC.^[1] MTSCC is a rare neoplasm and is considered a low-grade entity. It may be a variant of papillary RCC.^[2] This tumor occurs throughout life (age range 17–82 years) and is more frequent in females.

Genetics

MTSCC does not have the characteristic molecular aberrations of papillary RCC: gains of chromosome 7 and 17 and loss of chromosome Y.^[3]^[4]

Diagnosis

MTSCC has a gross appearance close to papillary RCC. Microscopically, it has three histologic components: mucin, tumor cells forming tubules, and spindle cells. It is characterized by the proliferation of cuboidal and spindle cells arranged in tubular or sheet-like arrays, typically with a mucinous or myxoid background.^[1]

Immunohistochemical staining

IHC close to papillary RCC profile: CK7+, AMCAR+, CD10-.^[5]

Morphological variants

MTSCC can be a difficult diagnosis due to its morphologic heterogeneity. Several morphological variants have been described, as the ‘‘mucin-poor variants’’, showing a predominance of tubular or spindle cell components and only minimal pale mucinous background. Focal papillations or papillary cores and foamy histiocytes can also be seen, creating confusion with papillary RCC. Helpful features for diagnosis are bland cytologic features and adjacent tubular and spindle cell components. Focal areas of clear cells and oncocytic cells can also be present.^[1]

Differential diagnosis

Papillary renal cell carcinoma: MTSCC may have some morphologic similarities to the more common papillary renal cell carcinoma (papillary RCC), particularly the basophilic tumors with prominent solid growth pattern with sarcomatoid transformation.^[6]

Prognosis

MTSCC is of low-grade malignancy. Some rare cases of lymph node metastasis and recurrence have been described. Two cases of MTSCC with sarcomatoid change have been described, one with widespread metastasis to distant organs, including lung and bone.^[7]

A spindled component is characteristic of MTSCC, but the presence of significant pleomorphism with prominent nucleoli and mitotic activity, and necrosis should raise concern for a sarcomatoid change. Microscopic necrosis can be seen focally in MTSCC. Its significance is unknown. The presence of any necrosis should be mentioned in the pathological report.^[1]^{[citation needed]}

References

^ ^a ^b ^c ^d Fine, S. W.; Argani, P; Demarzo, A. M.; Delahunt, B; Sebo, T. J.; Reuter, V. E.; Epstein, J. I. (2006). "Expanding the histologic spectrum of mucinous tubular and spindle cell carcinoma of the kidney". The American Journal of Surgical Pathology. 30 (12): 1554–60. doi:10.1097/01.pas.0000213271.15221.e3. PMID 17122511.
^ Shen, S. S.; Ro, J. Y.; Tamboli, P; Truong, L. D.; Zhai, Q; Jung, S. J.; Tibbs, R. G.; Ordonez, N. G.; Ayala, A. G. (2007). "Mucinous tubular and spindle cell carcinoma of kidney is probably a variant of papillary renal cell carcinoma with spindle cell features". Annals of Diagnostic Pathology. 11 (1): 13–21. doi:10.1016/j.anndiagpath.2006.09.005. PMID 17240302.
^ Cossu-Rocca, P; Eble, J. N.; Delahunt, B; Zhang, S; Martignoni, G; Brunelli, M; Cheng, L (2006). "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". Modern Pathology. 19 (4): 488–93. doi:10.1038/modpathol.3800565. PMID 16554730.
^ Brandal, P; Lie, A. K.; Bassarova, A; Svindland, A; Risberg, B; Danielsen, H; Heim, S (2006). "Genomic aberrations in mucinous tubular and spindle cell renal cell carcinomas". Modern Pathology. 19 (2): 186–94. doi:10.1038/modpathol.3800499. PMID 16258504.
^ Paner, G. P.; Srigley, J. R.; Radhakrishnan, A; Cohen, C; Skinnider, B. F.; Tickoo, S. K.; Young, A. N.; Amin, M. B. (2006). "Immunohistochemical analysis of mucinous tubular and spindle cell carcinoma and papillary renal cell carcinoma of the kidney: Significant immunophenotypic overlap warrants diagnostic caution". The American Journal of Surgical Pathology. 30 (1): 13–9. doi:10.1097/01.pas.0000180443.94645.50. PMID 16330937.
^ Dhillon, J; Amin, M. B.; Selbs, E; Turi, G. K.; Paner, G. P.; Reuter, V. E. (2009). "Mucinous tubular and spindle cell carcinoma of the kidney with sarcomatoid change". The American Journal of Surgical Pathology. 33 (1): 44–9. doi:10.1097/PAS.0b013e3181829ed5. PMID 18941398.
^ Paner, G. P.; Srigley, J. R.; Radhakrishnan, A; Cohen, C; Skinnider, B. F.; Tickoo, S. K.; Young, A. N.; Amin, M. B. (2006). "Immunohistochemical analysis of mucinous tubular and spindle cell carcinoma and papillary renal cell carcinoma of the kidney: Significant immunophenotypic overlap warrants diagnostic caution". The American Journal of Surgical Pathology. 30 (1): 13–9. doi:10.1097/01.pas.0000180443.94645.50. PMID 16330937.