R-017507

Clickez sur l'image pour agrandir, ou sur les textes en gras pour visionner les imges ou les pages liés . Pour revenir à l'Observation, pressez Précédente dans votre navigateur

Click on the picture to Zoom or highlighted text to view the linked pictures or pages, . And Back on your browser to review the Observation

 

Présentation Clinique

Patiente de 48 ans tabagique, ayant une hypothyroidie sous Eltroxine, connue migraineuse, présente depuis deux mois une toux et des expectorations blanchâtres avec une consolidation de la base pulmonaire gauche persistante malgré une antibiothérapie.

Evaluée par bronchoscopie et biopsie à 2 reprises sans évidence de malignité. Apparitions de plusieurs petits nodules et d'images rapidement progressives pulmonaires au Scan de contrôle. 

R-017507001RX.jpg (168358 bytes)  R-017507002S.jpg (184024 bytes)  R-017507003S.jpg (195149 bytes)  R-017507004S.jpg (192437 bytes)  R-017507005S.jpg (227393 bytes)

Les divers moyens non invasifs de diagnostic n'ayant abouti, une résection segmentaire a été décidée.

Pathologie

Macroscopie

R-017507-01MA.jpg (233525 bytes)  R-017507-02MA.jpg (216465 bytes)

La segmentectomie ventrale du lobe supérieur droit montre sur coupe une lobulation du tissu pulmonaire par place accentuée, réhausse par un aspect luisant de la tranche de section. Des zones compactes blanchatres (droites sur les images) s'intercalent et se fondent avec le tissu pulmonaire plus rosâtre (vers la gauche).

Microscopie

R-017507-03A.jpg (521777 bytes)  R-017507-04B.jpg (500934 bytes)  R-017507-05C.jpg (455102 bytes)  R-017507-06D.jpg (420961 bytes)  R-017507-07D.jpg (444611 bytes)  R-017507-08D.jpg (471622 bytes)

Les coupes objectivent une architecture alvolaire conservée, et marque par un revètement épaissi s'arrètant au niveau de certaines traves fibreuses interlobulaires. Les septa alvolaires sont tapissées par des pneumocytes en continuité avec un épithlium cylindrique ( x 100, x 200, x 400 ). Ce dernier présentant un caractère sécrétoire apical, présente des zones de transition vers un épithélium plus cuboide, non sécrtant.

R-017507-09C-PAS.jpg (426732 bytes)  R-017507-10D-PAS.jpg (373710 bytes)  R-017507-11C-BA.jpg (497981 bytes)  R-017507-12D-BA.jpg (362972 bytes)

Les caractères sécrétants et non sécrétant sont exacerbés par les colorations au PAS (x 200, x 400) et au Bleu Alcyan (x 200, x 400 )

 

Diagnostic proposé:

Adenocarcinome bronchioloalvolaire, de type mucineux, prédominant.

 

Bronchioloalveolar carcinoma

(Ackerman's Surgical Path. 8th Ed.)

Bronchioloalveolar carcinoma can present in various forms that bear an important relationship to its prognosis: a single peripheral nodule, multiple nodules, and a diffuse pneumonic-like infiltrate. The latter two forms may involve several lobes or even be bilateral. Often the surgeon is not aware that the lesion is a neoplasm. Microscopically, bronchioloalveolar carcinomas have been divided into mucinous and nonmucinous types.

The mucinous type has a glistening appearance on gross examination; there is usually preservation of the underlying lung architecture, with occasional distortion of airspaces by pools of mucus. Microscopically, the tumor is formed by well-differentiated mucin-containing columnar cells that line respiratory spaces without invading the stroma. The tumor nodules have a topographic association with bronchioles rather than bronchi. Continuity between tumor cells lining alveoli and the epithelium of respiratory bronchioles or alveolar ducts can be demonstrated. A sharp separation is often found between the neoplastic and the normal cells, a useful diagnostic feature.

The reported cases of benign, borderline, and welldifferentiated malignant mucinous lung tumors are probably histogenetically related to the mucinous type of bronchioloalveolar carcinoma. The differential diagnosis includes primary adenocarcinoma of the conventional type and metastatic adenocarcinoma. Bennett and Sasser compared 30 cases of bronchioalveolar carcinomas with 100 cases of ordinary lung adenocarcinoma and found frequent overlapping patterns. Other authors have reported the presence of multiple foci of bronchioloalveolar carcinoma in association with conventional carcinoma. The main differences encountered between the two tumors were a higher incidence of multiplicity and a slightly better survival rate in the patients with bronchioalveolar carcinoma. Most authors, including ourselves, feel that the features of bronchioloalveolar carcinoma are distinctive enough to warrant their separation from the other subtypes of adenocarcinoma. Interestingly, the incidence of bronchioloalveolar carcinoma seems to be on the rise.

The nonmucinous type of bronchioloalveolar carcinoma (which comprises 60% to 75% of the cases) presents grossly as gray-white foci of parenchymal consolidation, sometimes associated with a central scar. Microscopically, the tumor cells are cuboidal rather than columnar and often have a bright eosinophilic neoplasm. The degree of nuclear atypia and nucleolar prominence is greater than in the mucinous variety. Apical spouts may be present as indicators of Clara cell differentiation. Hobnail cells may be present. Cilia are exceptionally rare; their presence should suggest the alternative possibility of a reactive condition. Eosinophilic intranuclear inclusions, which are PAS-positive and which are made ultrastructurally of bundles of microfilaments, are commonly seen.


In contrast to the mucinous type, various degrees of interstitial fibrosis and chronic inflammatory cells (some of which are S-100 protein positive) are usually present. When the fibrosis is extensive, the tumor is referred to as the sclerosing variant. Psammoma bodies are found in 13% of the cases.

Ultrastructurally and immunohistochemically, mucinous bronchioloalveolar carcinomas show differentiation toward bronchiolar goblet cells, whereas the nonmucinous types comprise cells with features of Clara cells and/or type 2 pneumocytes, the former predominating.

Alpha-1-antitrypsin is a useful marker for Clara cell differentiation, and surfactant apoprotein is a specific marker for type 2 pneumocytes. The latter cells are identified ultrastructurally because of lamellar inclusion bodies. Exceptionally, foci of endocrine differentiation are detected.

The nonmucinous type of bronchioloalveolar carcinoma is more likely to be solitary and has a better prognosis than the mucinous type. Sputum or bronchial washing cytology is almost invariably negative in cases that present as single peripheral nodules but is often positive (up to 88% of the cases) for the multinodular and pneumonic-like forms. Percutaneous fine needle aspiration has been used successfully for the detection of this tumor.

The existence of a benign counterpart of nonmucinous bronchioloalveolar carcinoma has been postulated, and the term papillary adenoma has been proposed for it. Another benign tumor allegedly composed of type 2 pneumocytes is so-called sclerosing hemangioma.