Alveolar soft part sarcoma: a clinicopathological and immunohistochemical analysis of 26 cases emphasizing risk factors and prognosis

Abstract

Objective: This study aimed to investigate the clinicopathological features and prognostic indicators of alveolar soft part sarcoma (ASPS).

Methods: The characteristics of 26 ASPS patients diagnosed at our hospital between January 2011 and January 2019 were retrospectively analysed.

Results: The data for 12 male and 14 female patients, with a median age of 27.5 years, were assessed. The clinical symptoms mainly included painless enlarged masses in deep soft tissues. ASPS had a characteristic pathological morphology. Twenty-four patients were positive for TFE3, and TFE3 gene rearrangement was detected in 12 patients. Among the 26 patients who completed follow-up, 14 had metastasis, 1 had local recurrence, and 7 died. Kaplan-Meier survival analysis revealed that prognosis was significantly correlated with sex, tumour size and metastasis (P < 0.05). Multivariate Cox regression analysis revealed that sex and metastasis were independent prognostic risk factors for patients with ASPS (P < 0.05).

Conclusion: ASPS is a rare soft tissue sarcoma of unknown origin that occurs in young people, has a slow but metastatic course, and is associated with a poor 5-year survival rate among patients with metastasis. ASPS has character TFE3 protein and gene expression, and the diagnosis is relatively specific. The diagnosis requires comprehensive analysis of clinical history, histological morphology, and immunohistochemistry.

Keywords: Alveolar soft part sarcoma; Clinicopathological features; Molecular features; Prognostic factors; TFE3.

Fig. 1

Microscopic imaging of haematoxylin and eosin (HE)-stained tumour cells. (A) Tumour tissue was separated into nodules of different sizes by coarse fibrous tissue. The cells are shown at 100× magnification after HE staining. (B) Tumour cells within nodules are arranged in a glandular vesicle shape, with rich intervesicular blood sinuses. The cells are shown at 200× magnification after HE staining. (C) Mitotic figures are observable at high magnification. The cells are shown at 400× magnification after HE staining. (D) Tumour cells of uniform size and shape (round or polygonal) are shown. Most of the cells are well defined, with abundant cytoplasm, and are translucent or eosinophilic. The cells are shown at 400× magnification after HE staining

Fig. 2

Histological and immunochemical assessment of tumour cells. (A) Tumour cell nuclei showing moderate-intensity expression of TFE3 (EnVision, 400× magnification). (B) Tumour cells with low Ki-67 value-added indices and nuclear expression are shown (EnVision, 400× magnification). (C) Tumour cell cytoplasm containing periodic acid-Schiff (PAS)-responsive rod-shaped crystals was observed at 400× magnification after haematoxylin and eosin (HE) staining. (D) TFE3 rearrangement visualized via breakapart FISH probes is shown. One male was positive for one red band and one fusion (1R1F)

Fig. 3

Kaplan–Meier survival curves indicating a correlation with (A) sex (P = 0.006), (B) maximum diameter (P = 0.031), and (C) the presence or absence of metastasis (P = 0.043) are shown. (D) Survival is shown to be unrelated to tumour location (P = 0.167)