Mucinous tubular and spindle cell carcinoma (MTSCC) is a distinct variant of renal cell carcinoma with mucinous tubular and spindle cell features (Srigley, 2004).

MTSCC occurs in patients with a wide age range. Affected patients range from 13 to 82 years old with a mean age of 53 and a male to female ratio of 1:4 (Srigley, 2004; Eble, 2003; Srigley and Delahunt, 2009).

Macroscopically, MTSCCs are well circumscribed tumors located centrally or cortically. Tumors range from less than 1 cm to greater than 18 cm in diameter and most tumors measure 2 to 4 cm. Cross sections of the tumor display uniform light tan, yellow or gray tissues with minimal hemorrhage and/or necrosis.
Microscopically, the neoplasms consists of small elongated tubules embedded in a background of basophilic mucinous stroma. There are areas of neoplastic cells arranged in curvilinear architecture separated by mucin. Closely parallel and collapsed tubular arrays with a spindle-cell appearance are noted (Figure 1). Tumors with focal neuroendocrine differentiation or sarcomatoid change have been reported (Kuroda et al., 2004; Dhillon et al., 2009).
Figure 2 shows positive cytoplasmic staining of CD10, CK7, and AMACR in neoplastic cells arranged in compact solid tubules and parallel cords.

In general, MTSCC possesses favorable prognosis. This tumor is considered as a low-grade carcinoma although one case with tumor metastasis has been reported (Dhillon et al., 2009).

MTSCC exhibits +7 and +20 in our current case (Figure 3). It has been shown that multiple chromosomal alterations including losses of chromosome 1, 4, 6, 8, 9, 13, 14, 15, 18, and 22 are involved (Rakozy et al., 2002). In addition, gains of chromosomes 12q, 16q, 17, and 20q identified by CGH analyses have been reported (Billis, 2002). Apparent gains of chromosome 7, 11, 16, and 17 have been observed (Rakozy et al., 2002; Billis, 2002).