Rare cutaneous metastasis from sarcomatoid carcinoma of lung
- 1 Canniesburn Plastic Surgery Unit, Glasgow Royal Infirmary, Glasgow, Scotland, UK
- 2 Pathology Department, Forth Valley Royal Hospital, Larbert, Falkirk, UK
- Correspondence to Ms Clare Josephine Tollan; cj_tollan@hotmail.com
Abstract
We present the case of a 57-year-old woman diagnosed with stage 4 sarcomatoid carcinoma of the lung who concurrently developed a scalp lesion, thought to be a cyst, which continued to grow and ulcerate. Excision revealed a rare case, only four previously reported in the literature, of metastatic sarcomatoid carcinoma of the lung. While a very unusual case, we would like to emphasise the importance of considering skin metastases when presented with unusual skin lesions, and importantly listening to the patient’s concerns, showing empathy and respecting their autonomy and referring to an appropriate specialist when considering the management of what may seem to be a minor skin report.
Background
Sarcomatoid carcinomas of the lung are poorly differentiated nonsmall cell lung cancers and are rare, representing less than 1% of all lung cancers.1 2 Prognosis of these tumours is poor2–5 with an average survival of 19 months from diagnosis, with a 5-year survival reported as 17.4%.3 The WHO (2015) classifies sarcomatoid carcinoma as a general term that includes pleomorphic carcinoma, spindle cell carcinoma, giant cell carcinoma, carcinosarcoma and pulmonary blastoma,1 and where possible, the specific subtype should be used as they are histologically heterogeneous although all poor prognostically.6 They occur most frequently in the upper lobes and are large (mean 7 cm) and often invade the chest wall.1 6 Risk factors for development include smoking, male gender and asbestos exposure.2 7 Symptoms are nonspecific and include cough, haemoptysis, dyspnoea, weight loss, fatigue and thoracic pain that maybe tumour localisation. Metastases of sarcomatoid carcinomas of the lung are reported to the bone and liver. Adjuvant chemotherapy or radiotherapy has not been shown to affect disease-free survival.3
We present a case report with an extremely rare occurrence of a sarcomatoid carcinoma metastasising to skin, and while this is a very rare occurrence with less than five such tumours reported in the literature,2 8 9 we feel that skin metastases should be considered as a diagnosis in any unusual looking skin lesion, especially when in a patient known to have a previous medical history of cancer.
Case presentation
A 57-year-old woman presented in early 2019 to her General Practitioner with pain in her left side, which was thought to be muscular. She was otherwise fit and well, had a busy lifestyle and was a nonsmoker. In July 2019, however, she found a painless soft tissue swelling over her left lateral 10th rib. MRI scanning diagnosed a primary left lower lobe tumour (40 mm), with hilar and mediastinal lymphadenopathy, and chest wall and hepatic metastases (T4 N3 M1c, stage 4c) CT and PET-CT confirmed findings with FDG avid right gluteal metastasis. Histopathological analysis and immunohistochemical staining of the ultrasound-guided biopsy of the rib mass revealed a nonsmall cell lung cell carcinoma with pleomorphic sarcomatoid features and the diagnosis of sarcomatoid carcinoma of the lung following further discussion with the sarcoma histopathologists.
Chemotherapy (carboplatin and pemetrexed) and immunotherapy (pembrolizumab) were commenced following diagnosis, in September 2019. At this point, the patient had noticed a small ‘lump on her scalp’, and with an ultrasound, it was decided that it was an innocuous cyst and needed no further treatment. Palliative radiotherapy (20 Gy in five fractions) to the chest wall in October 2019 eased symptoms and reducing the size of the soft tissue mass. Unfortunately by the beginning of 2020, transfusion-resistant checkpoint inhibitor-induced autoimmune haemolytic anaemia and severe immune-related colitis meant treatment had to be discontinued for a course of steroids. In February 2020, CT scanning diagnosed a further liver lesion and disease progression, with no targetable mutations and severe side effects from treatment, it was felt that the patient would not be a good candidate for further immunotherapy or chemotherapy.
In March during the period of UK lockdown for the COVID-19 pandemic, the patient presented with symptoms of high temperature and cough and tested positive for COVID-19. The patient was admitted to hospital for 16 days although fortunately never required respiratory support. Subsequently the patient developed an intussusception as a complication of metastatic disease, indicative of colonic involvement, and this was managed conservatively.
During the period between September 2019 and May 2020, the patient was aware that the lesion on her scalp had continued to grow and was now ulcerated, caused her pain and preventing her from sleeping comfortably, in addition to causing embarrassment. She again discussed it with her new oncology team, having moved city, and they also advised against seeking further treatment as it was still thought to be a cyst that was comparatively trivial compared with her illness, and also that a skin lesion would have no priority in the National Health Service due to COVID-19’s burden on services. The patient was upset that her concern was dismissed and discusses this in the Patient’s persepctive.
Through personal perseverance, the patient sought a further opinion on her scalp lesion from a plastic surgeon and said she was not surprised when it was suggested that this could clinically be a skin metastasis from the rare lung cancer. A biopsy from the scalp lesion histologically was confirmed as a malignant spindled tumour, and when correlated with the original lung pathology, morphological and immunocytochemical appearances were almost identical. The features were consistent with a metastasis to the skin from the original lung a pleomorphic sarcomatoid carcinoma.
Investigations
Soft tissue swelling over ribs, histology report, October 2019
The initial biopsy from the soft tissue lesion infiltrating the rib showed a malignant tumour composed of large cells with a myoid and spindled appearance. The nuclei were large and pleomorphic. And the cells expressed cellular adhesion molecule (CAM) 5.2, CD10, vimentin and a portion were positive for p63. Immunochemistry with activin receptor-like kinase (ALK) 1 was negative. The biopsy was considered to represent a nonsmall cell lung carcinoma with pleomorphic sarcomatoid features.
Skin lesion scalp, histology report, June 20
The biopsy from the skin lesion from the scalp showed features of a morphologically similar malignant spindled tumour extending through skin, with eosinophilic spindled cells with a myoid appearance. Again, the cells expressed CAM 5.2, CD10, vimentin and p63 (expressed in carcinoma). The morphological and immunocytochemical appearances were similar to the previously described sarcomatoid lung carcinoma.
Differential diagnosis
Undifferentiated spindled tumours of the scalp skin are a common diagnostic dilemma for the dermatopathologist and as many divergent diagnoses can show this pattern immunocytochemistry must be performed in order to subtype the tumour for treatment purposes.2 The vast majority of these tumours represent spindle cell squamous carcinoma (cytokeratin positive) or spindled melanoma (S100 and melan A positive) and if the tumour shows no definite lineage by immunocytochemistry (ICC), then a deeply invasive tumour fits best with a diagnosis of pleomorphic dermal sarcoma of skin. Other primary spindled tumours are less common (such as leiomyosarcoma (desmin positive) or angiosarcoma (CD34/CD31 positive)), and metastatic spindled tumours are extremely rare indeed and are unlikely to enter a working differential diagnosis unless there is a relevant history.
Clinically the lesion was thought to represent a skin metastasis. Rapidly growing ulcerating skin lesions may represent any of the common skin cancers including squamous cell carcinomas and melanomas. Differential diagnosis may also include cylindroma, atypical fibroxanthoma, dermatofibrosarcoma protuberans, poorly differentiated angiosarcoma and leiomyosarcoma.2
Treatment
The scalp lesion was fully excised, diameter 5 cm, and was reconstructed with a split thickness skin graft from her thigh.
Outcome and follow-up
Sadly the patient has died.
Discussion
Cutaneous metastases occur in 0.7%–0.9% of patients with cancer.10 Visceral organ malignancies have been reported to metastasise to skin in 1%–2%, breast being the most common followed by lung, oral mucosa, colon, stomach and oesophagus11 with adenocarcinoma being the most common histological subtype.8 12 Skin metastases should be a consideration when a patient known to have cancer presents with a new skin lesion and should also be a differential diagnosis for skin lesions with an unusual appearance. Metastatic skin deposits are often misdiagnosed as cysts or benign adnexal neoplasms, and they may be asymptomatic or be associated with pain and tenderness.10 They may initially present as a rapidly growing subcutaneous or dermal nodule with intact overlying epidermis13 but can also present as macules, plaques, nodules, pigmented tumours or mimic inflammatory dermatosis. Most cancers present as single nodules although some such as metastatic melanoma and those of unknown primary often have multiple nodules.14 Clinical suspicion is required and histological examination is required to make the final diagnosis. Metastases may mimic primary skin tumours histologically (as in this case) and a full previous medical history including previous malignancies (s) must be presented to the pathologist on the request form if an accurate diagnosis is to be achieved for the patient.
Immunohistochemical analysis often plays a significant role in determining the origin of the tumour. For example, cytokeratin expression (eg, AE1, AE3, CAM5.2), s indicative of a carcinoma, leucocyte common antigen or CD45 is present in cells of lymphoid origin, and melan-A, S100 and SOX(SRY-related HMG-box)-10 are markers of melanoma. The tumour may not be associated with epidermis or skin appendages suggesting a metastatic origin.8 Histological diagnosis of sarcomatoid carcinoma requires adequate sampling due to morphological heterogeneity.1 3 4 Keratin antibodies and CAM 5.2 staining may be positive, and immunohistochemical staining for cytokeratins CK18 and CK7. P63 is a sensitive marker for squamous differentiation. Our patient had a positive CAM5.2 and p63 in both chest wall soft tissue and skin metastasis specimens. CD10, a cell membrane neutral metalloendopeptidase,15 expressed in tissues including the lung, intestines, breast and kidneys, was also expressed in this tumour and has been shown to be expressed in 40%–68% of sarcomatoid carcinomas.2 16 17 Vimentin, although entirely nonspecific, a mesenchymal marker, may be positive in sarcomatous regions (as it was in our patient),7 and with the positive types of CK are indicative of a sarcomatoid carcinoma.8 The latest WHO guidelines for classification of lung tumours (2015) recommend molecular testing for histological components associated with known genetic abnormalities.5 18 19
Excision of metastases if surgically feasible and desired by the patient, when balanced with morbidity and mortality, following informed consent, can improve quality of life. Improvements can be both functional and psychological. Our patient was suffering from discomfort, difficulty in sleeping and the psychological burden of the visibility of her scalp lesion on a daily basis compounded by the view that this was ‘vanity’ from the medical profession. Discussion with and referral to a dermatologist or plastic surgeon to adequately assess the patient and propose possible treatment plans, providing the patient with the correct information and autonomy to decide on the course of management appropriate to their situation should be considered. Timely excision of growing skin tumours can prevent the need for increasingly complicated reconstruction with skin grafts or flaps, and similarly the ability to perform any surgery under local anaesthetic rather than regional and general anaesthetic.
Patient’s perspective
As I reflect on my medical journey, I feel strongly that I have not been taken seriously by the medical profession at crucial points in my disease. My cancer symptoms were dismissed by my GP in the early stages and it was only when there was physical evidence on my rib that my request for a scan was accepted. Unfortunately by this point, cancer had spread to my ribs, liver and buttock. Additionally, my anxiety over the lump on my head was also dismissed as verging on a vanity request with doctors continually brushing it aside until it was so large the procedure eventually required a skin graft and, disappointingly, private funding to action. This would not have been the case had it been taken seriously much earlier.
I am very grateful to the plastic surgeon for diagnosing the lesion as malignant, recommending removal and my private insurer for approving the procedure to go ahead right away. Feedback from oncology was very negative about the procedure as they advised of a risk that the skin graft would not take and I would be left with an open wound. They recommended that the lesion had radiotherapy to reduce. I did not want to go through the trauma of this procedure and also felt that it would prolong my considerable discomfort and distress as the lesion was clearly visible, embarrassing and I could not sleep properly. So with the plastic surgeon’s support and my acceptance of the risk, I proceeded with the proposed surgery. I am delighted with the result and cannot thank him enough for his quick diagnosis and action. Without this, I believe the lesion would have spread much further and would have had to experience the trauma of radiotherapy to the head.
Learning points
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Consider skin metastases if you see an unusual looking skin lesion, especially in patients with known cancer.
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Clinical correlation and previous medical history are extremely important when providing sufficient information to the pathologist, including previous histology reports located at different hospitals.
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In palliative patients, there should be the same consideration of the symptomatic and psychological benefits. Treatment may be possible as a local anaesthetic procedure, minimising risk.
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Prompt treatment of growing skin lesions reduces the need for reconstruction with increasing size.
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Respect patients’ autonomy and wishes, and ability to make decisions. Take care not to trivialise concerns including psychological benefits of treating skin lesions. The recently published report ‘First Do No Harm’ highlighted our failings as a profession in this respect and it is saddening to see the same sentiments reflected by our patient here.
Acknowledgments
We would like to acknowledge the valuable contributions of our patient to this case report and for the ‘Patient’s perspective’. Our patient sadly died before submission of this manuscript.
Footnotes
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Twitter @CjSivarajan
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Contributors Sections as described by BMJ case reports noted below and initialled for contributions of authors. Conception (AM, CM) and design, acquisition of data or analysis and interpretation of data (CJT). Drafting the article (CJT) or revising it critically for important intellectual content (CJT, CM, AM). Final approval of the version published (CJT, CM, AM). Agreement to be accountable for the article and to ensure that all questions regarding the accuracy or integrity of the article are investigated and resolved (CJT, CM, AM).
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Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
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Competing interests None declared.
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Patient consent for publication Next of kin consent obtained.
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Provenance and peer review Not commissioned; externally peer reviewed.
- © BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.
References
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