"Cannon-Ball" skin metastases as the presenting manifestation of lung adenocarcinoma.

Sir,

A 60-year-old male farmer (with a history of smoking 16 “bidis” per day for 40 years) presented with a history of multiple progressively increasing painless swellings on his anterior abdominal wall for the past 3 months. He also reported constitutional symptoms (anorexia and weight loss of approximately 40%). He had developed a cough with occasional blood-tinged sputum in the last month before presentation. On examination, seven large cutaneous nodules [Figure 1] were observed over the anterior abdominal wall with the largest being 3.7 cm × 2.1 cm. These were plum colored, hard, nontender without any discharge and ulceration. Rest of the physical examination was unremarkable. Chest radiograph showed a mass in the right hilum [Figure 2a] and computed tomography of the chest revealed a mass measuring 4.3 cm × 3.7 cm in the right upper lobe with loss of fat planes with right main pulmonary artery along with right hilar (level 10R) lymph nodes and multiple cutaneous nodules [Figure 2b]. A flexible bronchoscopic examination showed mucosal infiltration in the right upper lobe bronchus with occlusion of apical and posterior segments. Fine needle aspiration cytology from cutaneous nodules [Supplementary Figure 1, available as online-only material at www.lungindia.com] and endobronchial biopsy [Supplementary Figure 2, available as online-only material at www.lungindia.com] were consistent with adenocarcinoma lung. Immunochemistry of above specimens showed tumor cells to be positive for pan-CK (AE1/AE3) and for CK7 [Supplementary Figure 3a, available as online-only material at www.lungindia.com] and negative for both CK20 [Supplementary Figure 3a, available as online-only material at www.lungindia.com] and p63 [Supplementary Figure 3a, available as online-only material at www.lungindia.com]. HIV serology was nonreactive. The endobronchial biopsy specimen was negative for EGFR gene mutations by real-time ARMS-PCR assay and for ALK gene rearrangements by D5F3 immunohistochemistry. A diagnosis of stage IV NSCLC (EGFR and ALK wild-type adenocarcinoma; T4N1M1b) was made, and the patient initiated on chemotherapy with pemetrexed and carboplatin.

Figure 1

(a and b) Clinical photograph showing large cutaneous nodules observed over the anterior abdominal wall

Figure 2

Chest radiograph showed a mass in right hilum (a) and computed tomography of the chest revealed a mass in the right upper lobe with loss of fat planes with right main pulmonary artery along with right hilar (level 10R) lymph nodes and multiple cutaneous nodules (b)

Fine needle aspiration cytology from cutaneous nodules showing features consistent with adenocarcinoma lung

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Endobronchial biopsy confirmed the diagnosis of lung adenocarcinoma

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Immunochemistry of fine needle aspiration cytology and endobronchial biopsy showed tumor cells to be positive for pan-CK (AE1/AE3) and for CK7 (a) and negative for both CK20 (b) and p63 (c)

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Skin metastases occur in cancer patients with a frequency from <1% to 10% although these account for only around 2% of all skin tumors.[1] In general, the presence or development of cutaneous metastases is a poor prognostic sign with expected survival ranging from weeks to months. The relative frequencies of cutaneous metastasis depend on gender and thereafter the relative frequency of different types of primary cancers in each gender. Therefore for women with cutaneous metastases, the most common sites of primary malignancies are breast, ovary, lung, and colorectal while in men, these are lung, colorectal, esophagus, pancreas, and stomach.[12]

Cutaneous metastasis is an uncommon presenting manifestation of lung cancer. Adenocarcinoma is the most common histological type of lung cancer and also the type most commonly associated with cutaneous metastasis. In the index case, the diagnosis of adenocarcinoma was confirmed from both the primary (lung) and metastatic site (skin). As mentioned earlier, demonstration of adenocarcinoma histology in skin nodules can represent metastases from a variety of solid tumors including lung, breast, stomach, colon, pancreas, thyroid, and prostate. As per current IASLC/ERS/ATS recommendations and the WHO classification of lung tumors, a combination of microscopic features and immunochemistry (positive adenocarcinoma marker [CK-7] and negative squamous cell carcinoma marker [p63]) was used for establishing the diagnosis of lung adenocarcinoma in the index patient.[34] The absence of activating EGFR gene mutations and of ALK gene rearrangements was not unexpected for this clinical profile (heavy smoking, male gender).[3] Treatment for metastatic lung adenocarcinoma without actionable mutations remains chemotherapy with pemetrexed being the preferred drug to be used in the platinum doublet.[5]

Historically, “Cannon-Ball” involvement of the dermis by lobules of pericyte-rich capillaries has been reported in acquired tufted angioma.[6] We use the term “Cannon-Ball” to describe cutaneous metastases observed in the index case whose appearance to the naked eye was similar to that seen on chest radiograph in case of pulmonary metastasis from a variety of extrathoracic primary cancers.[7]

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Conflicts of interest

There are no conflicts of interest.