Low-Grade Fibromyxoid Sarcoma: A Clinicopathologic Study of 33 Cases With Long-Term Follow-Up
(Am J Surg Pathol 2011;35:1450–1462)

讨论：1.低度恶性纤维粘液样肉瘤的好发年龄？部位？预后有关因素？
      2.与伴巨大菊形团的梭形细胞肿瘤是否为同一个谱系？二者预后有无差别？
      3.低度恶性纤维粘液样肉瘤与硬化性上皮样纤维肉瘤是否为同一种肿瘤的两个不同端？
      4.到底如何给予这种肿瘤的镜下认识？
Abstract: Cases listed in the U.T.M.D Anderson Cancer Center
files as low-grade fibromyxoid sarcoma and originally diagnosed
before 2004 were reviewed. They were included in the study if
the diagnosis was confirmed and if there was adequate histologic
material and clinical information with at least 5 years of follow-
up. Thirty-three cases met the study criteria. The patients were 6
to 52 years old at the time of diagnosis (median, 29 y); 19 were
male and 14 were female. The most common tumor locations
were the shoulder area (5), thigh (5), and inguinal area (4).
Tumor size varied from 1.5 to 16 cm (median, 9.4 cm) in those
cases in which it was known. The typical histologic findings were
contrasting fibrous and myxoid areas, moderate to low
cellularity, bland-appearing spindle cells with no or slight
nuclear pleomorphism and rare mitotic figures, and a swirling,
whorled growth pattern. Prominent vascularity in myxoid areas
and perivascular hypercellularity were fairly common, whereas
larger hypercellular zones were sometimes seen in primary
tumors but were more frequent in recurrences (local) and
metastases. Hypercellular regions sometimes had round rather
than spindle cells, a diffuse sheet-like cell arrangement, and/or a
somewhat increased mitotic rate. Very hypocellular fibrotic
areas were also observed and sometimes had thick collagen
bundles. Pericollagenous rosettes were present in 6 cases but not
in all specimens from these. Other growth pattern variations
included storiform, fascicular-herringbone, and patternless
areas; uncommonly noted were cell clusters, strands, palisades,
and a retiform network. Additional unusual features were
moderate nuclear pleomorphism (seen mostly in recurrent and
metastatic tumors), cysts, osseous metaplasia, and a tigroid
pattern with alternating fibrous and myxoid strips. One patient
had a recurrence with features of sclerosing epithelioid
fibrosarcoma, whereas 2 had dedifferentiated recurrences with
anaplastic predominantly round cells and numerous mitotic
figures. Fourteen patients died of tumor after 3 (this patient’s
tumor became dedifferentiated) to 42 years (median, 15 y).
Nineteen patients were alive at last follow-up of 5½ to 70 years
(median, 13 y), 6 with tumor and 13 without. Twenty-one
patients had recurrence after intervals of up to 15 years (median,
3½y), and 15 had metastases (mostly in the lungs and pleura)
after periods of up to 45 years (median, 5 y). Except for
dedifferentiation, which led to short survival after it occurred,
histologic differences were not related to tumor behavior or
patient survival. The 4 patients whose neoplasms measured
< 3.5 cm were all tumor free at last follow-up.