Limits...
Diagnostic features and subtyping of thymoma lymph node metastases.

Sioletic S, Lauriola L, Gallo E, Martucci R, Evoli A, Palmieri G, Melis E, Pizzi G, Rinaldi M, Lalle M, Pescarmona E, Granone P, Facciolo F, Marino M - Biomed Res Int (2014)

Bottom Line: Three cases of lymph node metastases, one case occurring synchronously with the primary tumor and one synchronously with the first relapse (both in intrathoracic location) and one case of metastasis observed in a laterocervical lymph node subsequently to two thymoma relapses were found.The metastatic nodes were variably but extensively involved in all cases.Thymoma lymph node metastases, although rare, can be subtyped according to the WHO classification on the basis of their morphological and immunohistochemical features.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Regina Elena National Cancer Institute, Via Elio Chianesi 53, 00144 Rome, Italy ; The Pennine Acute Hospitals NHS Trust, Royal Oldham Hospital, Rochdale Road, Oldham, Manchester OL1 2JH, UK.

ABSTRACT

Aim: The purpose of the present study was to characterize the morphological features of thymoma metastases in lymph nodes and to evaluate the possibility of their subtyping according to the 2004 WHO classification of thymus tumors.

Materials and methods: We reviewed 210 thymoma cases in our series of thymic epithelial tumors (TET), including their recurrences and lymphogenous metastases. Three cases of lymph node metastases, one case occurring synchronously with the primary tumor and one synchronously with the first relapse (both in intrathoracic location) and one case of metastasis observed in a laterocervical lymph node subsequently to two thymoma relapses were found.

Results: The metastatic nodes were variably but extensively involved in all cases. The histological features were similar in both primary tumors and metastases. Thymoma metastases were subtyped according to the WHO classification as B3 (one case) and B2 (two cases), and distinctive features in comparison to metastatic epithelial neoplasias from other sites were observed.

Conclusion: Thymoma lymph node metastases, although rare, can be subtyped according to the WHO classification on the basis of their morphological and immunohistochemical features. Clinically, the presence of nodal metastases may herald subsequent relapses and further metastases even in extrathoracic sites.

Show MeSH

Related in: MedlinePlus

(a) Case 1, HE, 200x. B3 thymoma metastasis in the lymph node. EC with scant cytological atypia are seen forming sheets and palisades around vessels. Two perivascular spaces (PVS) are seen. (b) Case 3, HE, 50x lymph node partial involvement by metastatic B2 thymoma. The subcapsular sinus is partially preserved. The immature T-lymphocyte-rich metastasis of B2 thymoma is seen on the right, whereas residual lymph node B cell follicles and T-cell areas are seen on the left.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4109419&req=5

fig1: (a) Case 1, HE, 200x. B3 thymoma metastasis in the lymph node. EC with scant cytological atypia are seen forming sheets and palisades around vessels. Two perivascular spaces (PVS) are seen. (b) Case 3, HE, 50x lymph node partial involvement by metastatic B2 thymoma. The subcapsular sinus is partially preserved. The immature T-lymphocyte-rich metastasis of B2 thymoma is seen on the right, whereas residual lymph node B cell follicles and T-cell areas are seen on the left.

Mentions: The lymph node involvement in Case 1 was subtotal; in Cases 2 and 3 the lymph node involvement was partial. Particularly, in Case 3 the preoperative ultrasonographic study of the laterocervical node suggested a partial lymph node involvement due to slight lymph node hilus displacement. US power Doppler evaluation showed poor and confused vascularisation within the nodule; the lymph node hilum was not clearly seen. In Case 1, the metastasis showed the features of type B3 thymoma, with EC growing in sheets and nests forming palisades around vessels, similar to the perivascular spaces (PVS) (Figure 1(a)). Few lymphocytes of both mature (CD5+/CD1a−/Tdt−) and immature (CD1a+, Tdt+) T cell phenotypes were seen scattered among the EC or in the perivascular spaces (PVS). The tumor expressed the typical keratin 19 positivity of thymoma; no CD5 or CD117 positive EC were found. In Cases 2 and 3, the lymph node architecture was partially preserved and the metastases were very similar to the primary B2 thymoma. No significant morphological differences were found in comparison with the primary tumor with respect to the neoadjuvant chemotherapy given in Case 2. In both cases, the metastasis and the normal lymph node were seen closely intermingled, without a plasmacellular reaction neither a fibrotic response surrounding epithelial nests (Figure 1(b)). In all cases, the formation of PVS, a typical feature of B2 thymoma and B3, was frequently observed. The scattered EC of the tumor and the scattered histiocytes conferred to the involved part of the lymph node, a “starry sky” pattern (Figure 1(b)). In Cases 2 and 3, IHC demonstrated both the EC nature, CK19 positive of the scattered “clear” cells (Figure 2(a)), and the immature CD1a+ phenotype of the T-cell rich areas, as well as the occurrence of immature T-cells in PVS (Figure 2(b)).


Diagnostic features and subtyping of thymoma lymph node metastases.

Sioletic S, Lauriola L, Gallo E, Martucci R, Evoli A, Palmieri G, Melis E, Pizzi G, Rinaldi M, Lalle M, Pescarmona E, Granone P, Facciolo F, Marino M - Biomed Res Int (2014)

(a) Case 1, HE, 200x. B3 thymoma metastasis in the lymph node. EC with scant cytological atypia are seen forming sheets and palisades around vessels. Two perivascular spaces (PVS) are seen. (b) Case 3, HE, 50x lymph node partial involvement by metastatic B2 thymoma. The subcapsular sinus is partially preserved. The immature T-lymphocyte-rich metastasis of B2 thymoma is seen on the right, whereas residual lymph node B cell follicles and T-cell areas are seen on the left.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109419&req=5

fig1: (a) Case 1, HE, 200x. B3 thymoma metastasis in the lymph node. EC with scant cytological atypia are seen forming sheets and palisades around vessels. Two perivascular spaces (PVS) are seen. (b) Case 3, HE, 50x lymph node partial involvement by metastatic B2 thymoma. The subcapsular sinus is partially preserved. The immature T-lymphocyte-rich metastasis of B2 thymoma is seen on the right, whereas residual lymph node B cell follicles and T-cell areas are seen on the left.
Mentions: The lymph node involvement in Case 1 was subtotal; in Cases 2 and 3 the lymph node involvement was partial. Particularly, in Case 3 the preoperative ultrasonographic study of the laterocervical node suggested a partial lymph node involvement due to slight lymph node hilus displacement. US power Doppler evaluation showed poor and confused vascularisation within the nodule; the lymph node hilum was not clearly seen. In Case 1, the metastasis showed the features of type B3 thymoma, with EC growing in sheets and nests forming palisades around vessels, similar to the perivascular spaces (PVS) (Figure 1(a)). Few lymphocytes of both mature (CD5+/CD1a−/Tdt−) and immature (CD1a+, Tdt+) T cell phenotypes were seen scattered among the EC or in the perivascular spaces (PVS). The tumor expressed the typical keratin 19 positivity of thymoma; no CD5 or CD117 positive EC were found. In Cases 2 and 3, the lymph node architecture was partially preserved and the metastases were very similar to the primary B2 thymoma. No significant morphological differences were found in comparison with the primary tumor with respect to the neoadjuvant chemotherapy given in Case 2. In both cases, the metastasis and the normal lymph node were seen closely intermingled, without a plasmacellular reaction neither a fibrotic response surrounding epithelial nests (Figure 1(b)). In all cases, the formation of PVS, a typical feature of B2 thymoma and B3, was frequently observed. The scattered EC of the tumor and the scattered histiocytes conferred to the involved part of the lymph node, a “starry sky” pattern (Figure 1(b)). In Cases 2 and 3, IHC demonstrated both the EC nature, CK19 positive of the scattered “clear” cells (Figure 2(a)), and the immature CD1a+ phenotype of the T-cell rich areas, as well as the occurrence of immature T-cells in PVS (Figure 2(b)).

Bottom Line: Three cases of lymph node metastases, one case occurring synchronously with the primary tumor and one synchronously with the first relapse (both in intrathoracic location) and one case of metastasis observed in a laterocervical lymph node subsequently to two thymoma relapses were found.The metastatic nodes were variably but extensively involved in all cases.Thymoma lymph node metastases, although rare, can be subtyped according to the WHO classification on the basis of their morphological and immunohistochemical features.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Regina Elena National Cancer Institute, Via Elio Chianesi 53, 00144 Rome, Italy ; The Pennine Acute Hospitals NHS Trust, Royal Oldham Hospital, Rochdale Road, Oldham, Manchester OL1 2JH, UK.

ABSTRACT

Aim: The purpose of the present study was to characterize the morphological features of thymoma metastases in lymph nodes and to evaluate the possibility of their subtyping according to the 2004 WHO classification of thymus tumors.

Materials and methods: We reviewed 210 thymoma cases in our series of thymic epithelial tumors (TET), including their recurrences and lymphogenous metastases. Three cases of lymph node metastases, one case occurring synchronously with the primary tumor and one synchronously with the first relapse (both in intrathoracic location) and one case of metastasis observed in a laterocervical lymph node subsequently to two thymoma relapses were found.

Results: The metastatic nodes were variably but extensively involved in all cases. The histological features were similar in both primary tumors and metastases. Thymoma metastases were subtyped according to the WHO classification as B3 (one case) and B2 (two cases), and distinctive features in comparison to metastatic epithelial neoplasias from other sites were observed.

Conclusion: Thymoma lymph node metastases, although rare, can be subtyped according to the WHO classification on the basis of their morphological and immunohistochemical features. Clinically, the presence of nodal metastases may herald subsequent relapses and further metastases even in extrathoracic sites.

Show MeSH
Related in: MedlinePlus