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LETTERS TO THE EDITOR
Year : 2022 | Volume
: 25
| Issue : 6 | Page : 1248-1250
An atypical case of dermatomyositis associated with clear cell renal cell carcinoma
Biswamohan Mishra1, Ankit Sachan2, Chandrasekhar Bal3, Achal K Srivastava1, Amlesh Seth2, Anubhav Narwal4, Mehar C Sharma5, Seema Kaushal4, Anoop Saraya6, Awadh K Pandit1
1 Department of Neurology, All India Institute of Medical Sciences, New Delhi, India
2 Department of Urology, All India Institute of Medical Sciences, New Delhi, India
3 Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India
4 Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
5 Department of Neuropathology, All India Institute of Medical Sciences, New Delhi, India
6 Department of Gastroenterology, All India Institute of Medical Sciences, New Delhi, India
Correspondence Address:
Achal K Srivastava
Room No. 60, Ground Floor, CNC, All India Institute of Medical Sciences, New Delhi - 110 029
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/aian.aian_748_22
How to cite this article:Sir,
A 43-year-old male without any co-morbidity presented with acute onset and progressive weakness of bilateral upper and lower limbs. Two weeks before presentation to us, he had developed a fever with generalized body aches. Two days into fever, he was unable to lift both hands above shoulder. At around the same time, he noticed difficulty in getting up from a squatting position. The weakness was progressive, and in a week's time, he was unable to stand even with support. He became bed-bound and needed constant nursing care and attention. A non-itchy reddish purple rash was noticed over the upper chest, back, and bilateral shoulders.
He was presented to us two weeks after the onset of the illness. Examination revealed a conscious, cooperative patient with a maculo-papular rash over the upper chest, back, and both shoulders [Figure 1]a. Muscles were tender on palpation; no thinning was noticed. Power in bilateral proximal upper limbs was Medical Research Council (MRC) Grade 2/5 and distally, it was 4/5, symmetrically. In the lower limbs, power proximally was 2/5 and distally 4/5, symmetrically. Deep tendon reflexes were symmetrically normal and also sensory examination.
Figure 1: Showing histopathology photomicrographs of the muscle, skin, and right renal mass biopsy specimens and the PET scan images. A maculopapular non-itchy rash was noticed over the back (1a). Photomicrographs of the muscle biopsy showing maintained fascicular architecture (H and E, 40x) with myofibers showing mild variation in size long with few degenerated fibres (1b, red oval) and mild endomysial inflammatory cell infiltrate (1b, blue oval; H and E, 200x), with an admixture of CD4 and CD 8 positive lymphocytes (1c). Photomicrographs of skin biopsy showed no evidence of basal cell degeneration or active vasculitis (1d, maroon oval; H and E, 200x). PET showing FDG avid solid nodule with well circumscribed margins and measuring 2 cm in diameter (yellow arrrow in 1e) with contrast enhancement noted in lower pole of right kidney suggestive of renal cell carcinoma. No FDG avid retroperitoneal lymph nodes noted. Microscopic image of the excised renal lesion showing round to polygonal shaped cells with abundant clear cytoplasm, consistent with the morphology of clear cell RCC (1f, red rectangle; H and E, 100x)Clinically, the possibility of inflammatory myopathy was considered, likely dermatomyositis (DM) or viral myositis. Investigations revealed a normal hemogram [Table S1], with elevated serum aspartate transferase (713 U/L, N <41 U/L) and alanine transferase (295 U/L, N <40 U/L). Serum creatine kinase (CK) was highly elevated (22,000.00 U/L, N–39-308 U/L). Electromyography showed a myopathic pattern with evidence of spontaneous activity in both upper and lower limb muscles. Muscle biopsy showed maintained fascicular architecture with mild endomysial inflammatory infiltration comprising an admixture of CD4 and CD8 lymphocytes [Figure 1]b, [Figure 1]c. A skin biopsy from the site of rash showed mild mononuclear cell infiltrate without any evidence of basal cell degeneration or active vasculitis [Figure 1]d. Based on these findings, diagnosis of DM was made. He was started on pulse methylprednisolone 1000 mg intravenous for five days, followed by oral steroids at 1 mg/kg/day. Subsequently, there was improvement in muscle power, and within the next one-week, power in the proximal bilateral upper and lower limbs improved to MRC grade 4/5 and distally to MRC grade 5/5, symmetrically. There was a concurrent reduction in serum CK levels (4740 U/L at four weeks).
18Fluoro-deoxy-glucose positron emission tomography (FDG PET) screening for underlying occult malignancy revealed an FDG avid solid nodule with well circumscribed margins and measuring 2 cm in diameter with contrast enhancement in the lower pole of the right kidney [yellow arrows in [Figure 1]e]. An elective laparoscopic right partial nephrectomy was performed after four weeks. Histopathology of the excised sample showed tumor in sheets with round to polygonal shaped cells with abundant clear cytoplasm, consistent with the morphology of clear cell renal cell carcinoma (RCC) [Figure 1]f. The patient made an uneventful recovery from surgery and was discharged on Mycophenolate Mofetil (MMF) 500 mg twice daily and oral prednisolone 30 mg once daily.
At six-month follow-up, the patient had made a complete recovery and there were no post-surgical complications either. Power was MRC grade 5/5 in all four limbs, and the rash had completely resolved. CK at the last follow-up was 154 U/L, a remarkable decline. The patient was modified Rankin score 0, having resumed his job and routine day-to-day activities.
DM is a rare inflammatory muscle disorder with estimates in the general population ranging from two to nine in every 100000 person per year.[1],[2] The association of DM with RCC is rare.[3] A literature search revealed only 10 case reports prior to this. A clinic-pathological comparison between the cases described and the present case is depicted in [Table S2]. In the present case, there was remarkable recovery following right renal partial nephrectomy, both clinically and in the values of serum CK. Six of the eight previously reported cases for whom full text was available [3],[4],[5],[6],[7],[8] had shown persistent clinical improvement following removal of the underlying renal lesion, with four of these reporting concurrent decline in the CK levels [Table S2].[5],[3],[6],[7] The rest of the two cases,[9],[10] reported either no improvement[9] or recurrent relapse.[10] Notably, the 72-year-old female reported by Ofori et al.,[9] had multiple other malignancies apart from RCC, which may have contributed to the persistence of symptoms of DM. The 27-year-old male with recurrent relapses had antibodies to NXP–2 during follow-up re-evaluation.[10]
Perifascicular atrophy on muscle histopathology, which is considered characteristic of DM, was reported in two of the ten cases [[Table S2], column 8].[5],[10] In the majority of the cases (five out of ten) described muscle fiber inflammatory infiltration similar to the present case, while in the rest of the three, no description was given. The present case, though notable for its lack of perifascicular atrophy and classic rash, had all other clinical and biochemical and electromyographic features suggestive of DM. In all the reported cases, renal cell mass was promptly treated with either excision or, if unfit for surgery, with ablation or chemotherapy.
Focal incidental renal lesions are commonly encountered on PET/computed tomography (CT) imaging. The vast majority of these lesions are benign.[11] Needless to say; in the present case also, the small right renal mass was initially considered as an incidental finding, possibly unrelated to the clinical picture of the patient. It is yet to be discovered whether an antibody or any other biochemical marker directly links RCC with DM. However, in all the cases described in the literature, any renal mass detected on a malignancy screen, which pre- or post-dated DM and underwent definitive treatment, resulted in clinical improvement in most patients [Table S2]. Accordingly, the urology team was pursued to operate on the malignancy as early as possible. The clinical and laboratory courses after nephrectomy showed that it was highly probable that DM in the present case was a paraneoplastic event. Clinicians should have a high degree of suspicion if they encounter an incidental renal mass in patients with DM, and instead of considering it as an incidentaloma, early removal of the lesion is most likely to result in clinical improvement. At the same time, more and more such cases need to be reported, such that better diagnostic and specific biochemical markers may be uncovered, resulting in early diagnosis and treatment.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
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