Histopathology 2014, 65, 434–439.
Correspondence Mediastinal adenofibroma: a case report DOI: 10.1111/his.12411 © 2014 John Wiley & Sons Ltd.
Sir: Adenofibromas are common tumours in the female genital tract, and are occasionally reported in the biliary tree.1,2 Thoracic adenofibromas are exceedingly rare, and the few reported cases in the literature are of pulmonary origin.3–5 The scarcity of pulmonary cases is reflected in the absence of the lesion in major textbooks and in the World Health Organization classification of tumours of the lung, pleura, thymus, and heart.6 We report the first case of a primary mediastinal adenofibroma. A 38-year-old Caucasian male with no prior medical history presented with shortness of breath and difficulty in walking. A chest X-ray revealed mediastinal fullness. A computed tomography (CT) scan confirmed the presence of a 110-mm well-circumscribed mediastinal mass with irregular punctate calcifications, adjacent to and anterior to the pulmonary artery. The lungs were clear. The patient underwent mediastinoscopy, lymph node sampling, and robot-assisted thoracoscopic resection of the encapsulated mass. No invasion into surrounding structures and no pleural deposits were identified. The patient’s symptoms were relieved immediately postoperatively, and he remains without clinical evidence of recurrence 1 year later. Gross examination revealed a 120 9 60 9 55mm, well-circumscribed and encapsulated, grey, firm to rubbery papillary mass with scattered yellow specks (Figure 1). Necrosis or haemorrhage was not identified. A small fragment of adipose tissue was adherent to the capsule. Histological sections demonstrated an encapsulated tumour composed of large, bulbous, hyalinized and fibrotic fronds covered by a single layer of cuboidal epithelial cells with clear and focally eosinophilic cytoplasm, distinct cellular borders, and round nuclei (Figure 2A, B). Chromatin was coarse, and nucleoli were inconspicuous. Mitotic figures were absent. Similar epithelial cells were seen trapped within the stroma, and formed gland-like structures, tubules, and trabeculae (Figure 2C). Hypocellular and densely fibrotic stroma contained scattered lymphocytes and plasma cells along with coarse calcifications (Figure 2B). Equally distributed stromal spindle cells with tapered ends lacked atypical features. Cleft-like spaces contained variable amounts of granular eosinophilic
Figure 1. The tumour is encapsulated, and the cut surface is grey, rubbery and papillary with yellow specks. No necrosis or haemorrhage is present.
debris, with cholesterol clefts and foamy macrophages. Adherent thymic parenchyma featured the usual cortical and medullary components; however, thymic parenchyma was not seen within the tumour (Figure 2A). The epithelial cells stained with cytokeratin AE1/ AE3, Cam5.2, CK7, EMA and TTF-1 antibodies, and were non-reactive with antibodies directed against CD34, bcl-2, calretinin, WT-1, vimentin, desmin, smooth muscle actin, S100, CK20, and thyroglobulin. Stromal cells were only positive for vimentin and focally positive for smooth muscle actin. Macrophages stained with vimentin and S100 antibodies, whereas lymphocytes stained for either CD3 or CD20, but not CD5. The encapsulated tumour architecturally resembled a phyllodes tumour, whereas the bland cuboidal epithelial lining cells resembled pneumocytes and Clara cells. This cytomorphology suggests a respiratory epithelial derivation. TTF-1 positivity strongly suggests that the lesion arose from sequestered pulmonary epithelium. The tumour may have developed as a pedunculated pleural-based lung mass that, over time, separated from the lung. Alternatively, the tumour may have arisen from ectopic lung tissue. However, the absence of either normal lung parenchyma or remnants of a bronchogenic cyst make this somewhat speculative. Although the lesion was adherent to the thymus, this observation should not be overemphasized, and does not necessarily suggest a thymic origin for the
Correspondence
A
B
435
Figure 2. A, The encapsulated tumour is adherent to thymic tissue, and is composed of large, bulbous fibrotic fronds. B, The fibrotic fronds are covered by a single layer of bland epithelium. Chronic inflammatory cells are present in clusters throughout the stroma. C, The epithelium is cuboidal, with clear and focally eosinophilic cytoplasm, distinct cellular borders, and round nuclei. Trapped epithelium within the stroma forms gland-like structures. (All images: haematoxylin and eosin.)
tumour. As the thymus arises from the third and probably fourth branchial pouches, TTF-1-positive cells are not present in this organ. Furthermore, intralesional thymic parenchyma was not seen on light microscopy or immunohistochemically. The non-infiltrative nature of the tumour, along with the benign cytological features, practically limits the differential diagnosis to non-carcinomatous lesions such as sclerosing haemangioma, solitary fibrous tumour, and thymic lipofibroadenoma. In summary, we present the first case of a mediastinal adenofibroma. This benign, encapsulated, biphasic tumour most likely arose from displaced pulmonary epithelium. CONFLICT OF INTERESTS
The authors declare no conflict of interests. Heba Durra Jasvir Khurana Douglas B Flieder1 Department of Pathology, Temple University Hospital, Philadelphia, PA, USA, and 2Department of Pathology, Fox Chase Cancer Center, Philadelphia, PA, USA C
Histopathology, 65, 434–439.
1. Seidman JD, Cho KR, Ronnett BM, Kurman RJ. Surface epithelial tumors of the ovary. In Kurman RJ, Ellenson LH, Ronnett BM eds. Blaustein’s pathology of the female genital tract. 6th ed. New York: Springer-Verlag, 2011; 679–784. 2. Varnholt H, Vauthey JN, Dal CP et al. Biliary adenofibroma: a rare neoplasm of bile duct origin with an indolent behavior. Am. J. Surg. Pathol. 2003; 27; 693–698. 3. Suster S, Moran CA. Pulmonary adenofibroma: report of two cases of an unusual type of hamartomatous lesion of the lung. Histopathology 1993; 23; 547–551. 4. Vitkovski T, Zeltsman D, Esposito M et al. Pulmonary adenofibroma: cytologic and clinicopathologic features of a rare benign primary lung lesion. Diagn. Cytopathol. 2013; 41; 991–996. 5. Wang Y, Xiao HL, Jia Y et al. Pulmonary adenofibroma in a middle-aged man: report of a case. Surg. Today 2013; 43; 690–693. 6. Travis WD, Brambilla E, Muller-Hermelink HK, Harris CC eds. World health organization classification of tumors, pathology and genetics of tumors of the lung, pleura, thymus and heart. Lyon: IARC Press, 2004; 9–124, 145–247.
Correspondence Mediastinal adenofibroma: a case report DOI: 10.1111/his.12411 © 2014 John Wiley & Sons Ltd.
Sir: Adenofibromas are common tumours in the female genital tract, and are occasionally reported in the biliary tree.1,2 Thoracic adenofibromas are exceedingly rare, and the few reported cases in the literature are of pulmonary origin.3–5 The scarcity of pulmonary cases is reflected in the absence of the lesion in major textbooks and in the World Health Organization classification of tumours of the lung, pleura, thymus, and heart.6 We report the first case of a primary mediastinal adenofibroma. A 38-year-old Caucasian male with no prior medical history presented with shortness of breath and difficulty in walking. A chest X-ray revealed mediastinal fullness. A computed tomography (CT) scan confirmed the presence of a 110-mm well-circumscribed mediastinal mass with irregular punctate calcifications, adjacent to and anterior to the pulmonary artery. The lungs were clear. The patient underwent mediastinoscopy, lymph node sampling, and robot-assisted thoracoscopic resection of the encapsulated mass. No invasion into surrounding structures and no pleural deposits were identified. The patient’s symptoms were relieved immediately postoperatively, and he remains without clinical evidence of recurrence 1 year later. Gross examination revealed a 120 9 60 9 55mm, well-circumscribed and encapsulated, grey, firm to rubbery papillary mass with scattered yellow specks (Figure 1). Necrosis or haemorrhage was not identified. A small fragment of adipose tissue was adherent to the capsule. Histological sections demonstrated an encapsulated tumour composed of large, bulbous, hyalinized and fibrotic fronds covered by a single layer of cuboidal epithelial cells with clear and focally eosinophilic cytoplasm, distinct cellular borders, and round nuclei (Figure 2A, B). Chromatin was coarse, and nucleoli were inconspicuous. Mitotic figures were absent. Similar epithelial cells were seen trapped within the stroma, and formed gland-like structures, tubules, and trabeculae (Figure 2C). Hypocellular and densely fibrotic stroma contained scattered lymphocytes and plasma cells along with coarse calcifications (Figure 2B). Equally distributed stromal spindle cells with tapered ends lacked atypical features. Cleft-like spaces contained variable amounts of granular eosinophilic
Figure 1. The tumour is encapsulated, and the cut surface is grey, rubbery and papillary with yellow specks. No necrosis or haemorrhage is present.
debris, with cholesterol clefts and foamy macrophages. Adherent thymic parenchyma featured the usual cortical and medullary components; however, thymic parenchyma was not seen within the tumour (Figure 2A). The epithelial cells stained with cytokeratin AE1/ AE3, Cam5.2, CK7, EMA and TTF-1 antibodies, and were non-reactive with antibodies directed against CD34, bcl-2, calretinin, WT-1, vimentin, desmin, smooth muscle actin, S100, CK20, and thyroglobulin. Stromal cells were only positive for vimentin and focally positive for smooth muscle actin. Macrophages stained with vimentin and S100 antibodies, whereas lymphocytes stained for either CD3 or CD20, but not CD5. The encapsulated tumour architecturally resembled a phyllodes tumour, whereas the bland cuboidal epithelial lining cells resembled pneumocytes and Clara cells. This cytomorphology suggests a respiratory epithelial derivation. TTF-1 positivity strongly suggests that the lesion arose from sequestered pulmonary epithelium. The tumour may have developed as a pedunculated pleural-based lung mass that, over time, separated from the lung. Alternatively, the tumour may have arisen from ectopic lung tissue. However, the absence of either normal lung parenchyma or remnants of a bronchogenic cyst make this somewhat speculative. Although the lesion was adherent to the thymus, this observation should not be overemphasized, and does not necessarily suggest a thymic origin for the
Correspondence
A
B
435
Figure 2. A, The encapsulated tumour is adherent to thymic tissue, and is composed of large, bulbous fibrotic fronds. B, The fibrotic fronds are covered by a single layer of bland epithelium. Chronic inflammatory cells are present in clusters throughout the stroma. C, The epithelium is cuboidal, with clear and focally eosinophilic cytoplasm, distinct cellular borders, and round nuclei. Trapped epithelium within the stroma forms gland-like structures. (All images: haematoxylin and eosin.)
tumour. As the thymus arises from the third and probably fourth branchial pouches, TTF-1-positive cells are not present in this organ. Furthermore, intralesional thymic parenchyma was not seen on light microscopy or immunohistochemically. The non-infiltrative nature of the tumour, along with the benign cytological features, practically limits the differential diagnosis to non-carcinomatous lesions such as sclerosing haemangioma, solitary fibrous tumour, and thymic lipofibroadenoma. In summary, we present the first case of a mediastinal adenofibroma. This benign, encapsulated, biphasic tumour most likely arose from displaced pulmonary epithelium. CONFLICT OF INTERESTS
The authors declare no conflict of interests. Heba Durra Jasvir Khurana Douglas B Flieder1 Department of Pathology, Temple University Hospital, Philadelphia, PA, USA, and 2Department of Pathology, Fox Chase Cancer Center, Philadelphia, PA, USA C
Histopathology, 65, 434–439.
1. Seidman JD, Cho KR, Ronnett BM, Kurman RJ. Surface epithelial tumors of the ovary. In Kurman RJ, Ellenson LH, Ronnett BM eds. Blaustein’s pathology of the female genital tract. 6th ed. New York: Springer-Verlag, 2011; 679–784. 2. Varnholt H, Vauthey JN, Dal CP et al. Biliary adenofibroma: a rare neoplasm of bile duct origin with an indolent behavior. Am. J. Surg. Pathol. 2003; 27; 693–698. 3. Suster S, Moran CA. Pulmonary adenofibroma: report of two cases of an unusual type of hamartomatous lesion of the lung. Histopathology 1993; 23; 547–551. 4. Vitkovski T, Zeltsman D, Esposito M et al. Pulmonary adenofibroma: cytologic and clinicopathologic features of a rare benign primary lung lesion. Diagn. Cytopathol. 2013; 41; 991–996. 5. Wang Y, Xiao HL, Jia Y et al. Pulmonary adenofibroma in a middle-aged man: report of a case. Surg. Today 2013; 43; 690–693. 6. Travis WD, Brambilla E, Muller-Hermelink HK, Harris CC eds. World health organization classification of tumors, pathology and genetics of tumors of the lung, pleura, thymus and heart. Lyon: IARC Press, 2004; 9–124, 145–247.
